XV Excalibur
The Royal Navy's 12-metre CETUS-programme extra-large uncrewed underwater vehicle, built by M Subs.
On 24 June 2026 the Submarine Delivery Agency awarded Plymouth's M Subs a GBP6.68 million sole-source contract to trial XV Excalibur, its 12-metre, 19-tonne extra-large uncrewed underwater vehicle, running to 1 May 2028.
Last refreshed: 24 July 2026 · Appears in 1 active topic
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XV Excalibur is the extra-large uncrewed underwater vehicle at the centre of the Royal Navy's CETUS programme, built by M Subs of Plymouth as the programme's sole designer.
At 12 metres long and 19 tonnes, it is the largest uncrewed underwater vessel the Royal Navy has trialled, giving CETUS a concrete engineering base years ahead of most of the Navy's other planned uncrewed classes, which remain design briefs rather than built vehicles.
Excalibur underpins the case for the wider Type 93 class named in the 2026 Defence Investment Plan, functioning as its funded proof of concept rather than a separate procurement effort.
Excalibur secures a funded subsea trial
The Submarine Delivery Agency's GBP6,680,147 sole-source award to M Subs on 24 June 2026 makes XV Excalibur the only funded subsea contract of its fortnight, running against a headline GBP5 billion autonomy plan that named no contractor for any uncrewed class.
At 12 metres and 19 tonnes, Excalibur becomes the largest uncrewed underwater vessel the Royal Navy has actually put under contract, built by M Subs of Plymouth as CETUS's sole designer through a trial running to 1 May 2028. That funded, dated reality sits well below the scale of the wider Defence Investment Plan's ambitions for Type 93 and its sibling classes.
What is XV Excalibur?
How much did the Royal Navy pay for the XV Excalibur trials?
How does the XV Excalibur trial connect to Britain's Type 93 warship?
