Nato countries that do not spend two per cent of GDP on defence spending are playing “Russian roulette” with the West’s future, Grant Shapps has warned, Ednews reports via The Telegraph.

In an article for The Telegraph to mark the military alliance’s 75th anniversary, the Defence Secretary argued that allies must accept we are now in “a pre-war world”.

Last year, just 11 Nato members met its two per cent target, first set almost two decades ago, with France and Germany among the nations that spent less on defence.

That figure is expected to rise to 18 this year, with Paris and Berlin recently announcing that they will hit the target in 2024 – but others in the 32-nation alliance have not done so.

Mr Shapps wrote: “We must look beyond that target to shore up our defences. Yet some nations are still failing to meet even the two per cent. That cannot continue. We can’t afford to play Russian roulette with our future.”

Referring to Nato’s anniversary, he said: “Paying tribute to Nato’s past is not enough. Today we must give urgent thought once again to the alliance’s future. We have moved from a post-war to a pre-war world.”

Lord Cameron, the Foreign Secretary, delivered a similar message on Wednesday during a two-day trip to Brussels for a Nato summit of foreign ministers.

He told allies spending two per cent on defence was the “best way to prepare for the American elections in the autumn”, in a clear reference to the possibility of a Donald Trump victory.

Mr Trump, the Republican presidential nominee, triggered outrage in February when he said he would “encourage” Russia to attack Nato members who were not hitting the spending target.

In a speech at a Royal United Services Institute conference in Brussels later on Wednesday, Lord Cameron raised concerns that younger people are not as pro-Nato as they were during the Cold War, saying: “We have to win the argument with Nato all over again with a new generation.”

He also warned that Nato would face a “very bleak future” if its allies allowed Vladimir Putin to succeed in Ukraine.

The tough messages to Nato allies come as the Conservative Party is locked in debate about how high to raise UK defence spending.

Currently, around 2.3 per cent of GDP is spent on defence. Rishi Sunak has an ambition to raise that to 2.5 per cent but has put no timeframe on when that would happen.