The Ministry of Defence has approved the procurement of the Small Diameter Bomb II as an interim standoff weapon for the F-35, months after the National Audit Office warned that funding for the capability had not been provided.

The NAO’s July 2025 report on the UK’s F-35 capability stated plainly that the aircraft lacked an effective standoff air-to-surface weapon, noting that “to acquire a more capable interim air-to-surface weapon the UK F-35 programme has requested funding for Small Diameter Bombs” but that “the MoD has yet to provide this funding.” The report further concluded that the UK had “not yet purchased an effective standoff air-to-surface weapon” for the fleet.

A letter from MoD Permanent Secretary Jeremy Pocklington to the Public Accounts Committee, dated 30 April 2026, now confirms that position has changed. Pocklington writes that “approvals have been given to proceed with a Foreign Military Sales (FMS) procurement of the precision-guided munition, Small Diameter Bomb (SDB-II),” which will provide the F-35 with an interim precision standoff capability until SPEAR-3 enters service. SPEAR-3 integration has been repeatedly delayed and is not now expected until the early 2030s.

The SDB-II is a glide weapon developed by RTX capable of engaging moving targets in all weather conditions at ranges significantly beyond those of the Paveway IV guided bomb currently carried by UK F-35Bs. It is already integrated on the F-35B and has been used operationally by U.S. Marine Corps aircraft, meaning the UK procurement does not require new integration work and can proceed relatively quickly through the Foreign Military Sales route.

George Allison
George Allison
George Allison is the founder and editor of the UK Defence Journal. He holds a degree in Cyber Security from Glasgow Caledonian University and specialises in naval and cyber security topics. George has appeared on national radio and television to provide commentary on defence and security issues. Twitter: @geoallison
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    • Hi TJ, I did some digging this morning and Aviation Week reported something similar 1st Dec 2025, so let’s hope there’s already some momentum that’s built up on the delivery by now. From Wikipedia the Australians have ordered 3900ish so I’m guessing they aren’t waiting around for a sovereign (ish) capability, like we are with Spear 3, so I’d imagine our SDB II order might be for less than 1000. The cynic in me says 300 ish!

  5. Great weapon, should be able to do rapid delivery. Two big orders in one day is unprecedented for this government.

  6. Great news, even with spear 3 available this weapon still makes sense to build out inventory.

    Seems like things were finally starting to move before today’s game of musical chairs started.

    • Spear 3 is not a waste, it’s a generation beyond SDB II and it will keep the F35 real vent for an extra decade or more.

        • SDBII has the same concept of a tri-mode seeker and datalink as Spear 3, but it has by most estimates half of the range and lacks the ability to communicate between a swarm of missiles in front. In that regard it is still more advanced than the US weapons in service at the moment.

          • SDB’s range is highly dependent on the release height and speed from the platform. Whilst Spear has a significantly longer range and can be released at low level due to its internal turbojet engine. SDB is purely a gravity bomb with a set of wings attached, to give it a glide range.

      • Wunderwaffe! We must have wunderwaffe in 5-10-whatever years time!
        A 95% capability right here, right now just won’t do!

    • GBU53 is a good weapon but Spear 3 will have greater range, keeping pilots safer. It will also have better swarming functionality. Additionally the EW version will bring even more features that don’t currently exist.
      Cancelling it would be a massive mistake.

      • Yes. I wonder what’s the point of a DIP if these announcements keep coming out?
        Your view, as a Labour man, on Burnham, Streeting, defence wise? I cannot bear to name A R…

        • If you think AR is bad, Miliband is just sitting in the background and he is just scary and he has a very strong backing group of activists and unions behind him.

          • Even worse. In an election he’d be trounced like last time.
            Yes, the talent in Labour’s Cabinet scares me.

            • I can’t think of a single member of the cabinet who I would trust. Then I look at the other parties and 🤔. K.B. seems capable. Mel Stride? I had coffee and cake with Farage years ago and he was certainly enthusiastic. I actually quite liked him but P.M.? I don’t know. As for the others Ed Davey or the Green Loony Front. What a choice we have my friend.

              • Morning my friend.
                Coffee and cake with Farage! That’s brilliant. I’ve met him twice and had conversations about various subjects, both times when out on campaign for him when he was UKIP and we were rubbing the establishments noses in it.
                Yep, so I’m loathed for that on here by certain posters. 👋
                Otherwise, always been a Tory, but I cannot support them any more after what they’ve done to the military 2010 on and for continuing New Labour’s mass immigration policies, despite talking tough.
                I went back to them in 2019, like many, to see off a certain J Corbyn.
                Covid mucked things up, but their behaviour was awful.
                For me, they’re finished. The sight of Kemi B bemoaning the state of the RN the other week? After they’ve been in power?
                It was like Groundhog day, back in 2010 Fox was also bemoaning the state of the military after Labour had spent 13 years cutting it, and look what happened. All words.
                I know you reference the debts they left but even so, austerity was wrong.
                No. Reform are out to utterly bury the Tories for basically not being true Conservatives, and doing rather well. Nigel warned them when he came back 2 years ago, and he warned Labour as well.
                So here we are.
                So where else do I go? Raving Loony party? There is nowhere but keep voting for the same failures who
                dominate Parliament, which I cannot do, and no way am I spoiling my ballot.

                • feel same mate. told my friend a conservative councillor the other day, if the Cons admitted there mistakes and stopped trying to blame labour for their policies it might be different. Stand up and admit u were wrong. Otherwise screw them.
                  Until labour give 16 year olds the vote to beat them anyway

                • Back in the days of UKIP with my mate Nige. 🍩 Only joking. A friend of mine was one of his team and the offices were about twenty feet from my office so I was invited to pop in when he came to visit. I have voted for both his outfits but I also have a very good local Tory M.P. so… . We’ll see. I thought a lot of people voted for the Raving Loony Party last time. They are in government after all.!

        • DM,
          Have read several articles concerning an MP named Alister Carns, a highly decorated former RM, and a current Labour Minister. Not certain re his political philosophy, but assume he would not voluntarily shaft HM forces. He may well be the best available relief pitcher to close out the final innings of the current game/parliament. There is a long and storied history of former military commanders serving as POTUS in your former Colonies, and generally considered to be above average in administration/performance. Thoughts? 🤔

          • Morning mate.
            Yes, the suggestion is he’s not just RM, but ex SBS to boot.
            I didn’t list him as don’t give him a cat in hells chance, the big beasts on the left will be moving in, they’re the ones who worry me.

            • Unfortunately there is a long history in the Labour Party of picking the weaker option that the union think they can manipulate, rather than the better candidate.
              When the Labour ship role was between the two Milliband brothers they picked the less capable of the two because the unions knew that David was too strong for them to control.
              Al Cairns would be my pick, ex RM , would have made Brigadier if he hadn’t left to go into politics. He is exactly what this country needs a non politician, politician. Who picks his battles and not afraid to fight.
              I believe Angela Raynor relies heavily on him for military matters .

        • Hi Daniele, my two cents worth, I can’t stand Wes Streeting, another Oxbridge professional politicans that’s never had a real job in their life. Angela is a genuinely decent person but I’m not sure she either wants the job or is cut out for it . I think Burnham is the best all round candidate choice but I still doubt he will be on the ballot. Personally I want Starmer to stay in until the end of the parliament and if he is still so unpopular (which he will be) then stand down for a new leader and have an election. Of the 7 labour MP’s I know personally and have spoke to in the last week only two want Starmar to go and five want him to stay and those MP’s are a broad spread across left and right. No one wants Streeting, no one is particularly keen on Angela either. If Burnham was an MP then he could probably carry it.

          My own personal view is the country needs stability and it’s highly unlikely anyone can do better in the job than Starmar has. Anyone who takes the job will be instantly unpopular. If anyone needs to go it should be Rachel Reeves.

          And if anyone in the country thinks either Zach Polanski and Nigel Farrage are going to do anything other than wreck the country one only has to look at the internal workings of both parties and the calamity in any council they have ever run. I come across people in Reform and the Greens regularly and they generally strike me as insane. I have never liked the Tories as a party but I have always generally liked any of their politicans I have comes across on a personal level and never feared them or generally doubted their competence but with reform it’s definitely different and the new greens are one step beyond them.

          I worry about an electorate that can look passed faults in party leaders like taking massive bribes for crypto billionaires and Russia or lying about almost everything in their lives including their name (Polanski)

          This is the s**t America is going through right now. The USA is probably big enough and strong enough to get away with such Hubris all be it at a massive cost to its power and prestige. We are not, we need to be smarter.

          • Generally agree with the exception that I think Reeves should also stay. Her ideas and discipline need a fair trial and it looks like the economy is moving in the right direction; it’s like turning an oil tanker. Easing trade with Europe will help. No govt seems willing or able to cut the benefits bill significantly. If there was one single move that would accelerate positive change it would be dropping the pension triple lock in favour of a less expensive, but still fair link to just one or two indices. That debate needs to start soon, before the next election. Burnham seems a genuine character; responsible, good communicator with a generous disposition. Apparently Greater Manchester has enjoyed growth 3x that of London. A positive outlook on life does bring results.

          • Well we’re polar opposites on Farage, so that’s fine.
            On Starmer, I actually agree, I too would prefer he remains, as I’m even more worried by those on the left behind him!!
            And also because I think a PM should have a proper mandate and be voted into power, not like Brown, Truss, Sunak.
            I checked out Streeting and Burnham defence wise, again, nice sounding words same as Starmer, but if they’re beholden to the backbenchers on your party what’s the point.
            Starmer has a huge majority, and any attempt to reduce the welfare state was met with rumblings from the backbenchers, for me, the far left in your party. Same with immigration reform, they want things “watered down”
            Translates as, no change, on we go, despite Reform winning left right and centre for EXACTLY that reason.
            We’ll blame Starmer instead, where often it os Labour and wider government policy that is turning people to Reform.
            That’s certainly the case with my wife and I.
            Will Burnham, Streeting, or anyone listen?
            Doubt it.
            Burnham seemed to have the greatest gravitas for me, leadership wise.

          • I agree re Zack Polanski and Nigel Farrage, both are grifters in it for themselves, just at opposite ends of the political spectrum. Both would be disastrous in different ways.

            Starmer was see as a steady pair of hands, not an inspirational leader like Blair or Boris, but a roll the sleeves competent manager.
            But the changes he has made have been glacial, and what the electorate want to see is changes to their lives. Now these are in part unrealistic, the government is not god. There are things more powerful than the government – recall how the bond market toppled Truss.
            However Starmer does appear to be a ditherer. Instead of publishing the DIP, the contents seem to be trickling out, contract by contract, only when it seems a decision has to be made and can’t be deferred any longer. Starmer’s desk appears to be the place where policies go to die or at least enter limbo…

            I was unimpressed by some of Burnham’s histrionics at times during the pandemic, which were unhelpful in maintaining the required messaging. But the growth in the Manchester region has been impressive.
            (Unfortunately a lot of the MPs are just generally poor. A former classmate of mine is a Labour backbencher, and she was the stupidest most gullible individual in the class 🤦🏻‍♂️.)

            As for the Tories, they screwed up when trying to rig the ballot for the membership. They won’t recover until they can get someone sensible like Cleverly in charge.

            • I agree, I think much of the issue is that the Starmer government is almost entirely staffed by former civil servants and government workers. Dither, glacial pace and low risk low returns strategies are seen not just as the norm but as a virtue. Rachel reeves philosophy is do as little as possible to rock the boat and expect growth to follow. Stability is the only policy.

              The last government was staffed almost entirety by “journalists”. Everything was about big announcements with little if any idea of how to enact things or much care about whether things ever got enacted.

              People are pissed off due to lack of economic growth and the fact is there is not economic growth because technology progress has been on the decline since the 70’s and the work force is shrinking because people are getting old.

              There is nothing any government can do to affect those two factors and there is certainly nothing that two con men like Farrage and Polanski can do about it.

              • People are pissed off because it’s in our national genes.😂
                “It is only necessary to raise a bugbear before the English imagination in order to govern it at will. Whatever they hate or fear, they implicitly believe in, merely from the scope it gives to these passions.”
                William Hazlitt

          • labour dont listen though. blaming the local election beating on the far right and cost of living.
            If they actually listened that working class people are sick of it all they might actually pull it back over next couple of years. No hope of that.

          • So, Starmer goes.
            Who do you choose?
            Who is least likely to be:
            On the string on the unions.
            LISTEN to people regards their concerns about immigration rather than just dismiss as “far right.”
            Fund Defence.
            Reform the Pensions issue.
            To me, Burnham seems like a leader, but isn’t concerned by any of which I list above. Which
            I note you too ignored.
            People want lower migration and greater intergration of those that are here. You, Labour, cannot keep running and hiding from it.
            Politicians have been running from it since Brown was caught insulting that lady, and you’re still getting a hammering in the polls. You then lunched left with Corbyn, as if that was ever going to work.
            Now, still not listening.
            When you stop and action change, people like Farage I suspect would vanish quite quickly and end up on LBC again.
            Till then, Reform will still be successful.
            So, back to my original question. Who would you choose?

            • I would note that the current government is doing a pretty bang-up job at listening to the country re. immigration. It’s falling significantly.

              The problem is that there is nobody who can match the rhetoric coming from the greens or reform, because it is not deliverable. Farage claims to be able to fund defence, stop immigration, and reduce taxes. Three things that require spending/less income. It’s not possible.

              And don’t get me started on the green policies.

    • Agreed again but I’m still concerned that the whole SPEAR SDB concept is more about the COIN wars we used to fight , Iraq, Afghan etc . I once sat through a rather lengthy but nonetheless less interesting presentation by the RN at Shrivenham when the whole then CVF concept was being sold to us as ‘ COIN Strike’ . Speaking personally I’d like to see our primary focus for stand off ref F35 being JSM . Far greater range, much bigger warhead and already being procured by most of our allies , Norway, Australia , Italy – even USAF too plus it works with the current software without having to wait for Block 4, Block 5 whatever or where we are now 🇬🇧👎🙏

  11. This is very very good news.. finally the carrier strike ground has an affective long range strike weapon as well as a weapon that can attack maritime targets out to 75kms.

    It also means that even outside of the CSG the RAF now has a maritime strike capability they have been missing since sea eagle was withdrawn 26 years ago.. it’s not perfect but it’s a 105Lb warhead and a 75km range.. with 8 carried internally and 24 in total that’s a nasty kick.

    • Yeah it’s a baseline capability at standoff ranges. An F-35 should be safe from most if not all threats at 75km and this was desperately needed. JSM would be nice for a heavier weight option with even greater range for semi-strategic targets but at least the UK CSG will now realistically be able to strike against any target, at least on some level.

    • Okay, so thats plus 16 external then. Is this is still with 2 AMRAAM and 2 ASRAAM? Wonder if the F35B could carry an AMRAAM on its ASRAAM rail?
      With the A10 Warthog being put to affective use in the Gulf whether its worth considering the podded cannon at all?

  12. This is great news, finally the F35 will have a standoff weapon.

    I wonder if there is a case to be made to integrate the storm breaker with the Typhoon. It’s cheaper than the storm shadow, has longer range than brimstone and can hit moving targets.

  13. The big question is how many is the UK going to buy? The level of munitions in the stockpile all throughout the UK is not even close to being acceptable.

    • Hopefully a reasonable amount as they are not to expensive. But remember it’s a limited use weapon for the UK. The RAF always use a paveway IV if they can.

      This is really about giving the carrier battle ground some stand off capability as well as SEAD/DEAD… the RAFs favoured bomb truck for bulk missions where it has an airbase in range will still be a typhoon and that has many options.

      In the end F35s are special children for special purposes and a paveway still kills almost everything you can think of.

      In the end I do think the MOD should consider storm breaker as a companion weapon to spear 3 not just an interim. Although spear 3 is far more capable ( double the range for ships, swarm capability ect) it’s going to be twice to three times the cost.. so stormbreaker can be used to add that stock mass.

    • Pot, kettle and black. I don’t think the US inventory of munitions is too healthy after its latest Gulf misadventure.
      Has Iran surrendered yet? Straits open? Nuclear materials secure? No ?? Oh dear!!

  15. A good demonstration of delay tactics by the US. Delay doing something you promised to do and you force the hand to buy what you make instead. Very good.

    • The US are good at that, all F-35 customers have experienced it, and if the US arsenal needs re-stocking their will be further delays. Note that may not be the case for SDB, but SM-2 and PAC-3 customers may be ‘whistling in the wind’.

    • Shows how important it is that GCAP succeeds. The leverage the F-35 gives the US over us would be unacceptable across the entire UK fighter fleet.

  18. Yep. The US is more than happy to sell their weapons to the UK.
    What a different tale it is with Meteor and Spear3.
    Lockheed Martin was first given funds to integrate the Meteror missile in 2019,. £400 million funding was provided in 2021. Quote, “The F-35 Joint Programme Office (JPO) officially awarded contracts to Lockheed Martin for the Follow-on Development Programme, which specifically assigned Meteor a place in the modernization queue,” However LM then said they have been too busy to do the work. Integration was delayed until 2025. Now the latest estimate for in service is the EARLY 30’s. I bet if it was an American weapon Lockheed would not have taken over a decade to integrate the weapon as they have with Meteor.

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