Gerard DeGroot: Time to blow up the myths surrounding Trident

DURING last Thursday's Prime Ministerial debate, a moment of epiphany occurred.

While the budget deficit was being discussed, Nick Clegg proposed that around 100 billion could be saved by not renewing Trident, a "relic" of the Cold War. One could almost feel the reverberations caused by millions of Britons nodding assent.

Clegg's intervention had huge symbolic importance because it suggested that he is something genuinely new, while the Tories and Labour are mired in the distorted logic of the Cold War. Gordon Brown and David Cameron visibly stumbled trying to defend a hugely expensive, essentially redundant, weapons system. If they had shown up to the debate in flared trousers, polyester shirts and shoulder-length hair, they could not have looked more old-fashioned.

The argument, of course, is not Clegg's alone. Alex Salmond has also railed against the way the "London parties" want to cut social services, instead of cutting Trident. Since 100bn is a figure that commands attention, both party leaders have derived considerable benefit from it.

Unfortunately, the matter is not as simple as Clegg and Salmond suggest.

Clegg will undoubtedly be in for a grilling during today's second debate, on Europe and foreign affairs because, frankly, the 100bn figure is as shaky as a two-legged stool. A 2006 Defence White Paper put the figure more accurately at 65bn over 30 years. Clegg and Salmond appear to have added together worst case scenario estimates for the cost of four submarines (14bn), thrown in 3bn for refurbishing warheads, another 3bn for infrastructure costs, and then added in running costs of 1.5bn/year, multiplied by 50 years, yielding a grand total of 95bn.

Scrapping Trident won't produce an instant saving of 100bn that can be neatly subtracted from the national debt. The upfront costs from 2012 to the end of the decade should not exceed 1bn per year – in other words, less than what some analysts calculate will be the weekly interest payment on Britain's massive debt.

So, should Clegg and Salmond apologise for trying to pull the wool over our eyes? Yes and no. Their guilt lies only in buttressing a basically sound idea with specious figures.

Scrapping Trident makes good sense but, as Clegg undoubtedly understands, trying to sell the plan on practical (as opposed to strictly financial) grounds raises all those tendentious arguments about nuclear disarmament that poisoned politics in the 1980s. Far better to talk about money than to raise the spectre of Michael Foot and unilateralism.

Foot aside, Britain's independent nuclear deterrent was a flimsy notion back in the 1980s and is an entirely spurious one now. In that sense, Clegg is admirably modern, Brown and Cameron hopelessly old-fashioned.

Scrapping Trident addresses a problem that plagues us now, instead of obsessing on a problem from the past. While an extra 1bn per year will not cure the national debt, it will buy a lot of armoured personnel carriers and body armour for British soldiers.