“Nine new Boeing P-8 Poseidon Maritime Patrol Aircraft to increase further the protection of our nuclear deterrent and our new aircraft carriers. These aircraft will be based in Scotland and will also have an overland surveillance capability.”

In welcome news for many, last years Strategic Defence and Security review confirmed that the United Kingdom will once again operate an effective maritime patrol aircraft.

The P-8 Poseidon, developed by Boeing, is designed to conduct anti-submarine warfare (ASW), anti-surface warfare (ASUW), and shipping interdiction, along with an electronic signals intelligence (ELINT) role. This involves carrying torpedoes, anti-ship missiles and other weapons.

The history of the aircraft dates back to June 2004, when the US Navy announced the selection of the Boeing multimission maritime aircraft, 737 MMA, and awarded a contract to Boeing for the system development and demonstration phase of the programme for the US Navy’s next-generation maritime surveillance aircraft. The aircraft was given the designation P-8A in March 2005.

Poseidon contains up to 7 crew computer consoles in its cabin, has an electro-optical and infrared sensor turret, a maritime surveillance radar and signal intelligence system. Its radar is capable of detection, classification and identification of ships, small vessels and surfaced submarines.

It also has coastal surveillance capability. The P-8 is fitted with advanced magnetic anomaly detection system for submarine tracking. The Poseidon can be used for search and rescue operations.

According to the US Navy, the aircraft in US service carries lightweight Raytheon Mk54 anti-submarine torpedoes. It may also carry other torpedoes, missiles, free-fall bombs, depth charges, mines, or sonbuoys in its weapon bay. Air-to-surface and air-to air missiles, such as Harpoon anti-ship missiles, SLAM or AGM-65 Maverick land attack missiles, and AIM-9 Sidewinders or AIM-120 AMRAAMs will be carried on the underwing hardpoints.

It has been speculated that the UK may elect to integrate Storm Shadow on the aircraft, as it had planned to do with Nimrod prior to the cancellation of the aircraft.

It is expected that up to 117 P-8A MMA aircraft are to be purchased by the US Navy to replace the fleet of 196 P-3C Orion maritime patrol aircraft which are approaching the end of their operational lives. The initial operational capability of P-8A was achieved in November 2013.

In August 2012, it was first reported that Boeing saw the United Kingdom as a market for the P-8, following the cancellation of Nimrod MRA4. After speculation every few months that the UK was going to purchase the aircraft, the UK announced its intention to order nine P-8 aircraft.

P-8 Poseidon Quick Facts, courtesy of Boeing

  • For the P-8, Boeing uses a first-in-industry in-line production system that leverages the best of Boeing Commercial and Boeing Defense for development and production.
  • The P-8 can fly up to 41,000 feet and travel up to 490 knots.
  • P-8 offers higher reliability – the 737 has a 99.8 percent dispatch rate, with more than 4,000 aircraft flying, and 6,600+ orders.
  • The P-8 is engineered for 25 years/25,000 hours in the harshest maritime flight regimes, including extended operations in icing environments.
  • The P-8 can fly in all flight regimes, and can self-deploy up to 4,500 miles from base without refueling.
  • Dual CFM-56B commercial engines each provide 27,000 pounds of thrust, greatly enhancing climb and flight characteristics over turboprop equipped aircraft.
  • Each engine is equipped with a 180KVA engine driven generator.  Combined with the 90KVA commercial APU, this provides 450KVA of power. P-8 possesses significant growth capacity for equipment with excess onboard power and cooling capacity.
  • P-8 has twice the sonobuoy processing capability and can carry 30 percent more sonobuoys than any maritime patrol and reconnaissance aircraft currently flying.
  • P-8 has the ability to control unmanned air vehicles (level 2 control-receive) to extend sensor reach.
  • P-8 offers commonality with 737 fleet and other military platforms that use the 737 airframe.

The aircraft are to be based at RAF Lossiemouth in Scotland and be used to protect the UK’s nuclear deterrent and new aircraft carriers. The P-8s are also to perform search-and-rescue missions and conduct overland reconnaissance.

Deliveries of the P-8 Poseidon are to begin before 2020, with three being in service before 2020.

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Alex Williams

I understand the feelings re: Nimrod, but having had first hand experience of the delays and overruns the project was experiencing c.2001, it came as no surprise when it was cancelled in 2010, more than a decade overdue. However, how wise is it in the long term to make us so beholden to foreign manufacturers, even those of a close ally like the US?

David Anthony Simpson

We have done that sort of thing for decades now. Not an issue

Sean Lord Power

No guessing who pays your pension ?

Alex Williams

David Anthony Simpson Indeed we have, but usually in times of emergency or procurement cock ups. Increasingly it seems to be deliberate policy to abandon home grown R&D


I do not see any issues with buying off the shelf proven systems against a home grown aircraft , not in today`s budget environment. Play it safe and get the capability into the force.

Dave Powell

Good to have a replace the nimrod

Sean Lord Power

a job Nimrod should be doing ?

Clive Thomas

[‘…sigh…’] shall we reinstate the Victors as well?

Tom Baker

This’ll be better than Nimrod

Alan Fraser Gordon

Clive Thomas no he wants the Valiants reintroduced ?

Dave Flak

So they can keep dropping out of the sky?

Sean Lord Power

note I said ‘should be doing’… but down piss pour project management we have to ‘buy in’ rather than manufacturer our own.. Many jobs (my own) lost because of pour management.. Nimrod was more than capable of the job.

Do move on please. The Nimrod died 6 years ago. Can we talk about something that matters and is going to happen. You can rabbit on about what might have been – and most talk about Nimrod knowing little or nothing about its many issues) / but the future is P8 now and thank heavens for that.

Craig Close

I think this is the problem, this nation now looks at everything as ‘sufficient’ or ‘capable’ why not go for the best? So what if it’s bought in, it has been because it’s the best or better.

Simon Stockley

The fact of the matter is that there should NEVER have been a 6 year gap where Britain could not provide her own MPA coverage. Yes the Nimrod project was doomed but we have been reliant upon US, Canadian and French MPA support ever since. It was a catastrophic decision. Hopefully the decision to purchase “off the shelf” and crew with the worlds best will enable us to protect our own nuclear deterrent and carriers again.

Albert Yome

Would be interesting to see how it compares to the Kawasaki MPA

James Gale

That evaluation was already done as the Japanese aircraft was over here a few years back. Impressive but logistically and technology wise would have been a challenge. The Poseidon offers the better platform.

David Anthony Simpson

If you look back on this group you will see earlier comparative articles- or try google!

Albert Yome

I suppose that commonality with civilian 737s is a great advantage.

Chris Henzel

It’s got some big shoes to fill

David Anthony Simpson


Chris Henzel

The legendary Nimrod

Tim Nichols

It was legendary alright. Legendary for being old, obsolescent and killing it’s crew!

David Anthony Simpson

The mission systems are largely what is in Metlin 2 or would have been in MRA4.

Danny Fitzgerald

Does anyone know what weapons the British P8’s will carry yet?


I thought the magnetic anomaly detector had been removed in the US version to reduce weight and increase range. I think some export customer added it back (I forget who) but it’s not part of the US standard fit is it?


India`s P-8s have the MAD boom.

Simon Stockley

The fact of the matter is that there should NEVER have been a 6 year gap where Britain could not provide her own MPA coverage. Yes the Nimrod project was doomed but we have been reliant upon US, Canadian and French MPA support ever since. It was a catastrophic decision. Hopefully the decision to purchase “off the shelf” and crew with the worlds best will enable us to protect our own nuclear deterrent and carriers again.

John Putley

At least we have some LRMP back and the role has not been given over to a private company.

Ian Petrie

The Nimrod project was a travesty of the highest order. The P3 is based on the most successful, reliable and numerous airliners flying, I’m sure it’ll serve the UK well! They should have based the Nimrod replacement on something commercially available like the 737, A320, Avro 146 instead of chasing the Comet.

Andrew Perrin

comet was a world class plane with a flaw that nobody forsaw sadley it cost our aviation companys dear to the us, sadley we haven’t been a s good sinse nimrod was world class its mod and government procurement that’s the trouble, build one start another keep the skills that’s the trouble we don’t hence delays and costs escalate and time slipage


Integrating digital manufacturing with hand built, prehistoric airframes was a stupid plan from the outset. MRA4 was a criminal waste of public money. As with several other types, the UK should have licensed proven US designs and built something that worked, straight away, and had a massive supply line behind it already.


The Indian Navy were the ones who added the MAD boom back onto the aircraft.

In the end this feels like a great decision. It was a shame about Nimrod, but time to move on. No amount of whinging on Defence blogs and forums is gonna change that.

Andrew Perrin

waste of money and bad hindsight by mod and a moron government nimrod needed 500million more for a world class plane they nscrapped it had the mod and goverments past used lojic in procurement and a real building plan things wouldent arrive late don’t work properly and built to last, leasons they fail tyo grasp over last 20years, when will the penny drop and they get it right


The US purchase numbers are staggering compared to our 9. Anyone know how the MOD comes up with that number?

A question on detection. Why aren’t tech devices implanted under the ocean in British waters or areas of security concern? Is there nothing out there to detect ship and sub signals? That doesn’t involve ship or aviation requirement? Seems odd we can send robots into space but yet having an under water radar to detect activity seems some way off.


They have been there for decades called SOSUS, several nets in several oceans.


The weaponary will be interesting. Can we resist the temptation to fit them out with our own weapons and other British specific tech and so delaying the effective introduction for many years.

Take the planes with the US weapons and we can be in business much faster and probably with a lot less cost.


I would bet on Stingray rather than Mk 54 for a start, we have to throw UK PLC some crumbs at least. I found this comment interesting “These aircraft will be based in Scotland and will also have an overland surveillance capability.”
Does that mean an MFR mod like AN/APS-154?

“Overland” isn’t the same as littoral or maritime. If this is the case, that 9 ship force is going to be very busy.

Graham Haxell

NZ needs at least 3 of these!

Jamie Farrington

Nz also needs some mk 200 bae hawks.

Max Baker

How many have we got

Christopher Kent

Getting 9 I think

Max Baker

Wow that’s a lot

Lawrence Pleszak

remember the adage if it looks right? This doesn’t look right to me.. nimrod looked right!!

Simply irrelevant

Lawrence Pleszak

its relevant to me and it is my opinion… which i am entitled to

Lawrence Pleszak

so shut your fave you pompous cit!!

Alan Radisic

Nimrod was worthless and ageing at its time of life. It needed to be replaced. If you have ever seen a p8 up close…. it looks right especially when combined with it capability. Yes you are entitled to your opinion…. does not mean your statement was relevant though. Maybe look it the word up and what it means.

Lawrence Pleszak

bearing upon or connected with the matter in hand; pertinent: Not my quote, thats from a dictionary… Perhaps you should check a words meaning before a stupid comment

Andy Priddy

Briitains new sub hunter eh. Another bloody plane made by the yanks. Whats wrong with using our own aero industrys

Kyle Greet

Chinook, C-130, C-17, Apache, E-3…. all “yank” aircraft. What’s wrong with them?

Andy Priddy

Nothing. But it would be nice if we thought about doing it ourselves. If we don’t use the skills we have, we will loose them.

David Anthony Simpson

We have and we are not losing anything. You really need to get your brain around the complexities and costs of defence procurement. Yearning for all UK supply is one thing – paying the immense price for it is quite another.

Alan Fisher

Don’t we have our own Aircraft Industry. Surely BAE or someone can design a plane for this purpose? We cannot rely on others to equip our armed forces.

Tom Tomarse Burnside

Just think that the MRA4 was practically there we would have this capability right now

No it wasn’t. Sweeping statement of limited accuracy.

Alan Radisic

Still had a long way to go. The wings were not an easy or cheap fix and may never have worked possibly

Thats not the point why invest all that money in an aircraft that was there to cancel it borrow other nations maritime aircraft which is a joke but we wont cancel an aircraft like the f35 which has been plagued with problems and huge rises in cost but we will still chuck money at that america even had to cut its f22 production to just a 183 aircraft just to fund the bloody thing its disgusting

Tony Singleton

9 a lot for a small country


Alan Radisic

Nice article.


who says we hav’nt under water detection systems in place?
come of it, just google it in and see where bases for underwater detection are in Scotland, and where sigint comes ashore.

Peter Snaith

Well its got to be better than an old Coastal Command Wellington with a magnetic mine De-gausing ring ??

George Reywer

The article states that the P-8 has a Magnetic Anomaly Detection system. The US P-8 do not have a Magnetic Anomaly Detector (the Indian ones do). Are the RAF ones being fitted with one?