Reality check: is Keir Starmer’s triple lock on nuclear weapons anything new?

The UK already has four Vanguard-class submarines, but there have been problems with their maintenance. Photograph: Danny Lawson/PA

Keir Starmer has announced a “triple lock” on Britain’s nuclear weapons policy as he seeks to portray Labour as the party of security in the general election campaign.

The Labour leader said his party would be “totally committed” to the UK’s submarine-based nuclear weapons programme, and that he would be prepared to authorise their use.