All governments are reluctant to cut defence spending, or rather be seen to do so. With Britain's self-image as a warrior nation and its belief that its armed forces really are "the best in the world", no politician will freely admit to reducing the defence budget.

But it is increasingly clear that the next government will have to make cuts of roughly 10-15 per cent in real terms. Even the Tories, who still see themselves as the party of the armed forces, will have to slash the defence budget if they are to maintain their commitment to ringfence health and international development spending.

The latest report from the Royal United Services Institute shows how these cuts could shrink the armed forces by up to a fifth (see graph). Although we can expect no mainstream Labour or Tory figure to make it, there is a strong case, given the £178bn Budget deficit, for cutting defence spending.

Data published by the Stockholm Peace Research Institute in 2009 placed the UK fourth in a table of the top ten military spenders in current US dollars. The US led the table, spending $607bn on defence, with China in second place, spending $84.9bn. France came in third place ($65.7bn) and the UK was just behind with $65.3bn. British defence spending as a percentage of GDP is 2.6 per cent.

Many will assume that Britain should fight to maintain its position in the international pecking order, but that ignores an alternative approach. Instead of struggling to project power abroad, we should focus on pursuing fairness at home. This means prioritising spending on education, health and anti-poverty measures.

In the post-recession world, this sceptred isle will be forced to become a more pragmatic and modest nation. The £20bn renewal of Trident, little more than a national virility symbol, must be cancelled. Military intervention abroad, humanitarian or otherwise, will become increasingly unthinkable.

It is a case that Labour should be prepared to make. As James Purnell wrote in his excellent Guardian article this week, by conceding that major spending cuts are needed in some areas, the government will be in a better position to argue that the deficit must not be cut at a rate that threatens economic recovery. Let's hope that Labour's "radical manifesto" reflects this truth.

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