In 1964, he returned to government after Harold Wilson defeated Alec Douglas-Home at that year's election.

[1] Seven months later, Peart became Leader of the House of Commons, taking the subsidiary title Lord President of the Council.

[1] After Labour lost the 1970 election, Peart returned to opposition as Shadow Leader of the House of Commons.

He served in those roles until 1982, when he was defeated for re-election by Lord Cledwyn of Penrhos in a vote among Labour peers.

[1] On 6 June 1975, Peart was on board the train which derailed in the Nuneaton rail crash; he survived with minor injuries.