Russia could be ready to attack Nato within five years and leaders of the western alliance are expected to agree to increase military spending to 5% of GDP this month to contain the threat, the alliance’s secretary general has said.

Mark Rutte said in a speech in London on Monday that Nato needed “a quantum leap in our collective defence”, which would include significant rearmament to deter an increasingly militarised Russia.

That would include a fivefold increase in air defence, thousands more tanks and millions more artillery shells to boost stockpiles and ensure Nato countries match existing levels of Russian production.