It comes as the new Labour government grapples with stretched public finances, which it has blamed on the "dire inheritance" left by the previous Conservative administration ousted from power in July.

Announcing the decisions in parliament, Healey said the assault ships HMS Albion and HMS Bulwark would be decommissioned alongside an ageing frigate and two support tankers.

Fourteen of the oldest Chinook transport helicopters will be removed early from service, and the lifespan of Puma support choppers will not be extended beyond March 2025.

Elsewhere, the Army's Watchkeeper drones, which have been in service for a decade but beset by problems and are now effectively obsolete, will be grounded.

"For too long our soldiers, sailors, aviators have been stuck with old, outdated equipment because ministers wouldn't make the difficult decommissioning decisions," Healey said.

"As technology advances at pace, we must move faster towards the future," he said.

The moves drew swift criticism from opposition MPs, pointing to the need for strong Western military deterrence amid Russia's war in Ukraine and escalating global tensions.

One Tory MP called it "a black day for the Royal Marines".

But Healey said the decommissionings would save pound500 million ($632 million) over five years, adding that those savings "will be retained in full in defence".

He also said that "these will not be the last difficult decisions I will have to make to fix the defence inheritance that we were left with".

"But they will help get a grip of finances now, and they will give greater scope to renew our forces for the future."

Britain spent an estimated 2.3 percent of GDP on defence last year, with the new government saying it intends to increase that to 2.5 percent by an unspecified date.