The Royal Navy has demonstrated for the first time that its new Experimental Vessel (XV) Excalibur can be controlled from the other side of the world, with operators in Australia directing the uncrewed submarine while it was submerged in UK waters.

The test, carried out in July during Exercise Talisman Sabre 2025’s “Maritime Big Play” series, was part of the AUKUS Pillar II programme to develop and share advanced technologies, according to a Royal Navy news release.

The 12-metre Excalibur is the Royal Navy’s first Extra Large Uncrewed Underwater Vehicle (XLUUV), unveiled earlier this year after a three-year development project known as Cetus.

Control of the UK vessel from a remote operating centre in Australia, more than 10,000 miles from its home at HMNB Devonport in Plymouth, marked what the Navy described as a milestone in uncrewed system interoperability. According to Commodore Marcus Rose, RN, Deputy Director Underwater Battlespace, “The XLUUV exercise was a big step forward in our ability to operate uncrewed systems interchangeably with Australia.”

The exercise also saw the UK, Australia, and the United States working with Japan to advance underwater acoustic communications. It follows AUKUS partners’ decision in 2024 to explore interoperability with Japan’s maritime autonomous systems as a first step in Pillar II collaboration.

Captain Keith Taylor, RN, the UK Senior Responsible Owner for Maritime Big Play, said in the release, “This exercise demonstrates how we are exploiting the learning from our experimentation, by applying it to the Royal Navy’s growing arsenal of Uncrewed Underwater Vehicles; taking experimentation into the hands of the war fighter.”

Maritime Big Play is a series of joint experiments aimed at integrating robotics and autonomous systems into naval operations. Building on last year’s events, the 2025 iteration placed greater emphasis on command-and-control across vast distances and in contested environments.

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

41 COMMENTS

  1. This seems like the most basic piece of internet control possible being heralded as a major accomplishment, my wife regularly controls the vacuum cleaner in our holiday house but she is not looking for a medal for that.

    • I’d say it was more worrying that Putin controls the US President. If trying to manage a relationship with a difficult (shall we say…) person like Trump in the UK’s best interest is ‘being controlled’ he’s doing a damn sight better job than his predecessors.

      • Manage? You mean behaving like a door mat. Starmer is a one term prime minister. Come 2029 Labour are gone. As for better, define it. 10% tariffs and a terrible trade agreement is better? Maybe buying F35A to carry american nukes on British soil is better? Or plunging the economy into permanent stagnation with 1.1% growth and a growing pile of debt coupled with the highest taxes in our history. No thanks.

        • Optimist or what?

          Doubt he is going anywhere soon. The Cons have hit a slope do deep it makes the Marianas trench look shallow and Reform are just hollow, forgive me, how often as the MP for Clacton been to er, his constituency, er, where is it, Clacton?

          Nope, Labour are in for at least another term. Time to drink your pint and dry your tears.

          • Those damn pensioners, fancy paying NI, tax and private pension contributions all their lives, and being sensible and some very frugal lives, in order to have a retirement! I’m sure the Socialist Workers Party we have in Government hopes they all die off pretty quick to save them having the money they are due!

          • Saccarine, we have some of the lowest State Pensions in Europe. BTW, I paid income tax and NICs for 50 years.

          • It’s not a bank account, morons.

            You paid taxes. That’s all. In fact, far less than you’re expected to take out with your free money.

            What a surprise the whingebag Boomers take that last bit away from the rest of us before they kick it. Couldn’t do anything for anyone else, would much rather bankrupt the country on the way out the door.

            “I paid tax and NI for 50 years” – yeah, nice one. You also paid the pensioners of your day an insulting and impoverishing pittance, you cretins. This is why I’m encouraging all of my friends to do what I did and leave Britain for countries that aren’t filled with the greediest pigs eating from the trough.

            • Wow someone needs to sit on the naughty step for being a bit of a baby frothy mouth. Anyone notice you left the UK? Nope!

              • Imagine being so poor and so bad at saving for your retirement that you need to depend on the State.

                Typical Boomer. It’s the lead in your brains.

                • Like I said, get on the baby step, as that’s where cry babies go! Dry your eyes, and stop blaming others for your failings in life!

        • You’ve forgotten how lick spittle Tory PM’s were to Trump. But no, you’ve convinced me. In just over a year he’s destroyed the magnificent legacy that fourteen years of Tory government left him. How could I be so blind ?

          • Who me? I can’t stand any of them. There all full of it. I just had to laugh at the suggestion that the current clown is somehow better than the previous ones.

    • More like ultra left back benchers and very small majorities in mainly Muslim dominated areas control the British Prime minister!

  2. “According to Commodore Marcus Rose, RN, Deputy Director of Underwater Battlespace, ‘The XLUUV exercise was a big step forward in our ability to operate uncrewed systems interchangeably with Australia. The operators initially complained of feeling dizzy, but after flipping their monitors upside down, they reported no further issues.’”

    Is this some kind of joke?!

    #Day3

  3. Is all this genuinely moving forward at pace or are we subject to the usual spin on the RNs autonomous expectations and hope for these capabilities? The RN needs to be moving at pace as they should be, and are, the priority for modernisation and an increase of war fighting capabilities.

  4. Somewhat OT but Trident replacement….Just read that the ‘Defence Nuclear Enterprise’ will cost us £200bn over 20 years. Ouch!

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