The Blyth Valley member has served in the role for 32 years, overcoming serious operations for cancer to campaign in the run-up to the last election.

Making the surprise announcement on Monday, he said: “After serious consideration and a long time in politics, I feel it is time to step aside.

“It has been an absolute privilege to serve the people of Blyth Valley and I sincerely thank them for all their support over the years.

“I feel that it’s time, at my age, that I was ‘put out to grass’.”

Mr Campbell was elected as a union representative in 1967 when working on the

coalface at Bates Colliery, and held NUM office until the pit’s closure in 1986.

He was elected in 1969 to Blyth Borough Council as councillor for Croft Ward, where he served until his election as MP in 1987.

Since then, he has became the longest serving MP in the constituency’s history,

having fought and won eight general elections.

Mr Campbell spearheaded flying pickets during the 1984-85 Great Coal Strike, and,

more recently, sponsored Jeremy Corbyn in the Labour leadership contest.

He has also been one of Labour’s most prominent pro-Brexit campaigners, putting himself at odds with some in his party.