Lib Dems and Tories divided over Trident Report
16 July 2013 Last updated at 19:52 BST
The coalition parties are at odds after a Lib Dem-prompted government report set out options for replacing the UK's Trident nuclear weapons system.
The Lib Dems favour reducing the number of Vanguard submarines from four now to three, saying the existing system was designed for the Cold War era.
Defence Secretary Philip Hammond said it would be "naive or reckless" not to have a like-for-like replacement.
Caroline Wyatt reports.