Mark Rutte said Britain will need to steadily increase defence spending to meet Nato target of 3.5% of GDP by 2035

Britain needs to show “a credible path” of annual increases in its defence budgets to meet a Nato target of spending nearly £30bn more on the military by the middle of the next decade, the head of the alliance said on Thursday.

Mark Rutte, Nato’s secretary general, said that Britain could not wait until just before 2035 to lift defence spending to 3.5% of GDP, in an unusually pointed intervention a day after he met prime minister Andy Burnham.