Burnham left with £4.7bn bill for Starmer’s new defence investment plan

Ally of PM-in-waiting says four-year boost for the armed forces is an unexploded bomb'

• Britain has finally grasped the nettle on defence, but tough choices lie ahead

Andy Burnham will have to find an extra 4.7bn for defence in his first budget, after Keir Starmer announced a 298bn defence investment plan (Dip) without having fully identified how it will be funded.

Sources close to the Makerfield MP said he would not try to renegotiate the Dip after the outgoing prime minister announced its details at a press conference on Tuesday.

47bn on new nuclear submarines, including the Dreadnought replacement for the Trident submarines and the new Aukus attack submarine project, being developed with Australia and the US.

13bn on a new nuclear warhead and 1.7bn on nuclear fuels. Another promise to pay 1bn for 12 Lockheed Martin F-35A jets capable of carrying nuclear bombs will come after 2030.

8.6bn on the development of the Gcap next-generation fighter aircraft in a joint project with Italy and Japan, plus an extra 1.1bn to keep existing Typhoons in service until the 2040s.

A total of 5bn more on drones, 1bn more than announced in last year's strategic spending review, with investments in air, land, sea and underwater drones to operating alongside soldiers, warships and fighter jets.