Four companies are preparing to bid for the nuclear submarine maintenance facility at Devonport in a move that could see BAE Systems wrap up the entire £25 billion Trident replacement contract, The Times has learnt.

BAE, Babcock, Carlyle Group and General Dynamics are all understood to have asked UBS, which is handling the sale of Devonport, for a prospectus.

KBR, a subsidiary of United States-based Halliburton, controls 51 per cent of The Devonport Royal Dockyard, or DML as it is called. It is understood that relations between KBR and the Ministry of Defence deteriorated so badly that KBR has effectively been forced into selling the dockyard.

The MoD is thought to be angry that Halliburton is floating its KBR subsidiary against British wishes and is selling to avoid risking the loss of maintenance contracts.

DML is thought to have been valued at up to £400 million by KBR. However, industry sources suggest that opening bids are likely to start at half this. With the UK planning to replace its Trident nuclear deterrent the opportunity to buy DML likely to be seized on by defence companies.

If BAE bought DML it would be responsible for building the Trident submarines at Barrow-in-Furness and then servicing them at Devonport.

Mike Turner, BAE’s chief executive, said last month that he was “very, very interested” in DML. Carlyle, the private equity group, is rumoured to want to join forces with BAE.

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