How much should Britain really be spending on defence?

Pressure, domestic and external, is growing on the government to increase defence spending markedly. Yesterday, the secretary general of Nato, Mark Rutte, called for member states to push their target beyond the 2 per cent of GDP set back in 2006, in the light of far greater international challenges. Donald Trump, possibly as a bargaining tactic, has called for a commitment to spend 5 per cent on defence (more than anyone spends now – and it’s actually currently below 4 per cent in the US).

There is obviously no shortage of real and potential trouble facing the Atlantic Alliance – Russian aggressions in Ukraine and Georgia; instability across the Middle East; and an increasingly assertive China. The most immediate threat is from Russian “grey zone” action by merchant vessels acting on behalf of Kremlin interests – notably tearing up vital communication cables in the Baltic. Can we find the money to defend ourselves?

Very simply put, it is to increase defence expenditure to 2.5 per cent of national income. This is described as “iron clad”, presumably like an original Dreadnought. However, unlike those Edwardian steam-powered sea monsters powering over the horizon, it is not obvious how and when this commitment will be achieved; no date has ever been set.

The Conservative opposition has raised this failure in the Commons, but to little effect. The most ministers will offer is that the “path” to the 2.5 per cent target being met will be published, like the overall public spending review, “in the spring”.

The Conservative MP Mark Pritchard had some fun with this, asking the minister, Luke Pollard, “Is that the astronomical spring, which he will note ends on 21 June, or the meteorological spring, which ends, from memory, on 31 May?” Pollard, the great sphinx of Whitehall, refused to be drawn.

The Conservatives, currently equally enraged by the decision to rename HMS Agincourt to save French blushes, are hampered in their attempts to wrap themselves in the flag because their own record on defence spending was fairly poor. It was further tarnished by some spectacularly wasteful projects, such as the new armoured car for the army. Indeed, the Tory-led coalition administration made defence a prominent target for cuts, in contrast to their performatively patriotic rhetoric.

A respectable, but no longer adequate, 2.3 per cent of GDP. The incoming Labour government boosted the budget by £3bn, which is the sort of sum that sounds impressive in the chamber or on TV but hardly registers in the bigger scheme of things – it amounts to 0.1 per cent of GDP. In total, defence spending is around £54bn, less than it was in the comparative calm of 2010.

Britain used to be one of the very few nations to even reach the 2 per cent target, but now some Nato members states are setting better examples – Poland spends more than 4 per cent, and Estonia in excess of 3 per cent. The laggards, still below 2 per cent, are Portugal, Italy, Canada, Belgium, Luxembourg, Slovenia, and Spain. In Nato, defence seems to get more important the nearer you get to Russia...

A row with Trump. Despite his apparently warm relations with Keir Starmer, the US president is unlikely to be impressed by even rapid progress to the 2.5 per cent figure – especially as sluggish economic growth means that it actually won’t amount to that much more in terms of troops, tanks and planes. If his recent form is anything to go by, Trump could then threaten Britain, other European allies and Canada with punitive trade tariffs if they “refuse to pay their bills”, as he sees it.

As a literal nuclear option, Trump might threaten to withdraw US troops from Europe, or even withdraw the nuclear umbrella and leave the alliance. In which case Europe really would have to get its act together and spend what’s needed to deter Vladimir Putin – a lot more than 2.5 per cent.

The crunch will probably come at the Nato summit in the summer, a forum where Trump has previously staged showdowns; informally, Trump will need to be placated by whatever plans the government announce in the spring, if Starmer wants to avoid being publicly humiliated.

It’s difficult. The long and gradual decline in defence spending after the end of the Cold War effectively averted an even worse cash crisis in the NHS than it is currently experiencing – the money saved by scaling back defence was spent on keeping hospitals going and dealing with an ageing population. Now, clearly, that trend has to go into reverse.

The weakness of the UK’s post-Brexit economy means there’s less money around for anything, though, and the Treasury is traditionally resistant to the generals’ pleas for more (especially when so much procurement cash is squandered). Politically – compared with, say, schools, healthcare or pensions – there are few votes to be had in expanding the armed forces.

Rachel Reeves always seems unmoved by the case for boosting defence. Whether the Trump Factor will change all that, we shall discover shortly.