Outgoing UK Prime Minister Keir Starmer said on Tuesday that Britain would spend a “record” of almost £300 billion ($397 billion) over the next four years to modernise its armed forces in the face of rising threats.

Starmer, expected to leave office next month after losing the support of Labour members of parliament, announced an extra £15 billion for defence spending up to 2030 when he launched his long-awaited Defence Investment Plan (DIP).

The plan, due to be published later on Tuesday, will see increased money for drones and autonomous systems as the nature of modern warfare changes.

“This record investment puts the security of the British public first, transforming our armed forces and giving them the funding and equipment they need to fight and defend our nation,” Starmer said.

The plan follows months of wrangling within the Labour government over the resources required to modernise Britain’s fighting capabilities to counter greater aggression from countries such as Russia, and a less reliable United States.

Two defence ministers quit earlier this month in a row over the defence plan, including defence secretary John Healey who said it risked making Britain “less safe”.

The resignations highlighted Starmer’s weakening authority.

He announced on June 22 he was stepping down after MPs from his ruling Labour party switched their support to veteran politician Andy Burnham.

Burnham, the 56-year-old former Greater Manchester mayor, will take over as prime minister in mid-July if he faces no challengers for the Labour leadership.

Starmer has called the defence plan “game-changing investment”.