Saudi Arabia has leapfrogged Britain, Japan and France to become the world’s fourth largest military spender, the Stockholm International Peace Research Institute (Sipri) announced today.

According to the institute, military spending in the Middle East had gone up 4 per cent in real terms, with Saudi Arabia’s up 14 per cent from 2012 to 2013 to reach £40 billion.

The rise makes the country one of 23 to double military spending since 2004.

Sipri said the rise could be down to increasing tensions with Iran, but that the desire to stave off Arab Spring-style uprisings with loyal security forces was likely a major factor.

Worldwide military spending saw a real-terms drop of 1.9 per cent in the period to £1.05 trillion, but this was skewed by the huge 7.8 per cent fall in US expenditure.

That was “the result of the end of the war in Iraq, the beginning of the drawdown from Afghanistan, and the effects of automatic budget cuts passed by the US Congress in 2011,” Sipri said.

Once the US is removed from the picture, spending actually increased by 1.8 per cent.

China’s budget increased 7.4 per cent, though this remained steady at 2 per cent of GDP.

It is the world’s second-biggest spender, though its estimated £113bn budget is less than a third of the £383bn spent by the first-place US.

“The increase in military spending in emerging and developing countries continues unabated,” said Sipri military expenditure chief researcher Dr Sam Perlo-Freeman.

“While in some cases it is the natural result of economic growth or a response to genuine security needs, in other cases it represents a squandering of natural resource revenues, the dominance of autocratic regimes or emerging regional arms races.”

Imperialist bloc Nato continued to account for well over half of the world’s military spending at around £570bn.

That was down around 6 per cent, driven in part by Nato’s belated military withdrawal from the Middle East but also austerity across much of Europe.