This article is more than 9 years old

This article is more than 9 years old

A defence minister has called for a jointly developed and run Anglo-French replacement for Britain's nuclear weapons, a move that would save the UK tens of billions of pounds and change the face of its defence strategy.

The proposal from Nick Harvey, a Liberal Democrat, was put to French defence experts at the French ambassador's residence this week. Harvey told the Guardian the idea was warmly received.

Britain currently has a capacity to have at least one of its ballistic missile submarines always at sea, fully armed, in an operational posture known as continuous at-sea deterrence.

France and Britain currently maintain four nuclear submarines, each armed during patrols with at least 16 intercontinental ballistic missiles and 40 or more warheads. Both countries face defence budgets that are under huge pressure.

The UK has agreed to make a decision on how to replace its Trident nuclear fleet in 2016 after the next election.

Harvey said: "The UK needs to revisit the case in the long term for the UK maintaining a permanent 24-7 at sea capability. We pay an enormous premium to maintain this. It is quite feasible that we could continue with a permanent at sea submarine patrol in conjunction with the French either with three British submarines as proposed to the current four.

"We could then rack up even bigger savings."

The idea, which is yet to be endorsed by the Conservative defence secretary, Liam Fox, is likely to provoke anger in the Tory party, partly because of concerns about loss of national sovereignty.

Harvey said: "We would be able to maintain separate command operations. "It is unlikely we would face circumstances in which Britain would be faced with an external nuclear threat that would not apply to the French national interest at the same time.

"It is quite possible for the French and British to work together on research and development of replacement submarines, so nearly halving the development costs. Over a 25 to 30-year cycle … the potential is to save many billions of pounds."

The idea of a joint Anglo-French deterrent has been raised by President Sarkozy in the past with Gordon Brown, but the then prime minister rejected the idea, fearing a negative reaction to the loss of Britain's independence.

Harvey as a Lib Dem minister is entitled under the coalition deal to maintain a separate position on Britain's deterrent.

"The UK-US relationship, including the defence relationship has been built up over 60 years, and our defence relationship with the French would take many years to develop, but both countries in terms of military industrial base need to co-operate much more," Harvey said.

The Labour leader Ed Miliband has questioned the need for a like for like replacement for Trident, a view that would not be popular across the Labour front bench. But a cut price Anglo-French bomb, once proposed by Lord Owen, might be attractive to Labour.

In November the Sarkozy and David Cameron signed a joint defence agreement leading to the two countries sharing facilities to maintain the safety of their independent nuclear deterrents.

The two countries have agreed to build a new hydrodynamics facility at Valduc in France and new technology development Centre at Aldermaston in the UK.