Can Britain still afford nuclear weapons ?
The four Vanguard class submarines which make up what is left of the UK deterrent come to the end of their lives around 2019 and their Trident missiles will need updating in the 2020s.
The go-ahead for replacement, which will cost some 20 billion pounds, was given by Tony Blair in 2006.
Cheaper alternatives, like having a ballistic missile system or a plane-delivered bomb or cutting the number of subs to three have been mulled over the last few years.
Some people would like to scrap the deterrent altogether, arguing it was never necessary in the first place and that the nature of threats to Britain has changed radically since the Cold War.
Others believe a minimum level of deterrence is vital given the proliferation of nuclear weapons into the Middle East and Asian regions.
What do you think? Is the need to balance our books so great as to end the 52-year British independent deterrent?