Procuring one less Successor submarine would produce savings of about £4 billion over the life of the system, Alexander says.
The U.K. has reduced its arsenal of nuclear weapons considerably since the height of the Cold War, removing its last air-dropped WE177 in 1998. The country now has 225 nuclear warheads, one of the smallest nuclear arsenals of any of the declared nuclear powers, Alexander pointed out.
“We have the ability to step down the nuclear ladder when we find the political will to do so.
“And the next great big step down the ladder is to reduce the salience of nuclear weapons in our Defense policy itself. And that means accepting that a Cold War-style continuous deterrent has become unnecessary,” added Alexander.
Ministers and former military commanders said that ending the deterrence patrols would be “weakening our national security” to save a “very small fraction” of the defense budget.
The review supports the purchase of the full fleet of Successor submarines and the retention of the continuous deterrence patrols, pointing out that the development of a new independent warhead for a submarine-launched cruise missile, fired from a modified Astute-class SSN would probable take more than two decades, long after the planned retirement of the Vanguard vessels.
Consideration was also given to an airborne deterrent capability dropped or launched from a large aircraft or the F-35 Joint Strike Fighter, allowing strike from the U.K.'s new aircraft carriers and land bases, but the report considers air-launched options too vulnerable to pre-emptive attack even if the aircraft are fitted with stealthy or non-stealthy nuclear- tipped cruise missiles.
None of the alternatives could “guarantee a prompt response in all circumstances,” the review stated. It also said that transitioning to any of the “realistic alternative systems” was now more expensive than a three- or four-boat Successor fleet.
The debate comes as the U.K. also considers what it may have to do if Scotland declares independence from the U.K. Naval Base Faslane on Gare Loch has been home to the U.K. ballistic missile submarine fleet since the age of the Polaris, but Scottish nationalists have a staunch non-nuclear policy and have stated that the deterrent ought to be removed. But with no place in England or Wales to harbor the submarines, the U.K. would be forced to unilaterally disarm if this scenario comes to pass.