Defense Secretary Liam Fox Wednesday told Members of Parliament that a study of alternatives to the so-called Trident program was also being prepared. That's an obvious nod to the Liberal Democrats, the junior coalition partner, which has in the past said developing and maintaining the very costly nuclear deterrent is unnecessary.
Critics of the system argue it is a remnant of the Cold War, adding that decision to renew it was rushed through Parliament to help BAE Systems, the British company that builds the submarines.
Fox would disagree. The conservatives are in favor of renewing Trident.
"The nuclear deterrent provides the ultimate guarantee of our national security," Fox said Wednesday. "We cannot dismiss the possibility that a major direct nuclear threat to the United Kingdom might re-emerge."
Fox had to admit, however, that Trident will be costlier than previously estimated.
Adjusted for inflation, the final price tag of the new submarines would be between $32 billion and $40 billion, up from the 2006 estimate of no more than $23 billion.
The price hike is in part due to a new nuclear reactor that's to be used in the submarines that's more expensive but also safer than previous models.
Trident has long been a divisive issue but now that defense budgets across Europe are forced to shrink, it's been more controversial than ever.
London last October announced it would cut defense spending by 8 percent but agreed not to make a decision on Trident until after the next election, which is scheduled for May 2015.
It's still up for discussion whether Britain needs three or four new submarines.
There has been speculation that Britain may share nuclear submarine capability with France, which has previously suggested it was open for cooperating on the nuclear deterrent.
Both powers in November signed extensive military cooperation deals that foresee aircraft carrier sharing, a joint rapid-reaction ground force, the coordinated development of high-tech arms and joint nuclear weapons testing.
It would be a major turnaround for traditional naval rivals France and Britain.
Both countries have a fleet of submarines armed with nuclear ballistic missiles, enabling them to have one sub constantly at sea to strike in case of an attack.