Facilities at Devonport won only partial clearance

Few details of the inspection have been released, but the BBC has learned that transfer has cost �417m instead of the �237m promised by DML.

Last month it emerged that the base had failed a nuclear safety test.

Workers at Devonport cheered when they won the contract to refit the Vanguard-class Trident submarines in 1993.

Union leaders at Rosyth had fought bitterly to keep the work in Scotland.

Campaign demands

They say they told the Conservative government of the time that the transfer plan was deeply flawed.

But they say they sympathise with the position of colleagues in the West Country.

Cheers greeted the Trident move to Devonport

The Plymouth-based Campaign Against Nuclear Radiation And Storage has pressed for a fuller report on the situation to be published.

The Royal Navy said the public should take reassurance from the toughness of the nuclear inspection.

Devonport is preparing to undergo a re-run of its annual safety inspection after failing a nuclear accident drill.

Exercise Kismet was held in September to test ability to cope with any submarine reactor accident.

The MoD said the failure was due to "a number of individual shortfalls in our management of the scenario".

Devonport has the largest military dockyard in Europe, covering 650 acres on the River Tamar, on the Devon-Cornwall border.

It is already home to Trafalgar-class nuclear-powered submarines, and is now the sole refit base for the Royal Navy's underwater fleet.