Britain will raise defence spending to 2.5% of GDP by 2027 and target 3% in the longer term by cutting its overseas development budget, Prime Minister Keir Starmer said on Tuesday.
"This government will begin the biggest sustained increase in defence spending since the end of the Cold War," Starmer told parliament.
The shift in Britain's defence strategy comes before Starmer flies to the United States to meet President Donald Trump on Thursday, who has repeatedly called for NATO members like Britain to spend more on defence.
European leaders were stunned earlier this month when Trump's administration made clear that Europe would need to step up to provide its own security, sparking a bout of diplomatic activity.
Starmer said that difficult choices needed to be made in the interest of the country's security and he would fund the increased spending on the military by cutting the aid budget from 0.5% of GDP to 0.3% in 2027.
"We will also set a clear ambition for defense spending to rise to three per cent of GDP in the next parliament," he added.
Successive British governments have reduced spending on defence since World War Two and the Cold War, as they stepped up investment in health, welfare and education instead.
Britain last spent 3% of GDP on defence in 1993/94.
