Jeremy Corbyn “in his heart of hearts is a Brexiter”, one of his longest-standing allies has said, backing up a suspicion critics held during the EU referendum.

Diane Abbott, who served as his shadow home secretary, said on Wednesday that Mr Corbyn is “anti-EU” and saw it as “a conspiracy of business people”.

He followed the party membership in supporting Remain in 2016 but many believed the veteran activist was unenthusiastic about the campaign.

Sir Keir Starmer served as Mr Corbyn’s shadow Brexit secretary but has now blocked him from running again as a Labour candidate for Parliament over his response to antisemitism.

The current Labour leader has sought to distance himself from his predecessor but Ms Abbott said the “only thing” that divided the pair in the past was Brexit.

She told the News Agents podcast: “Jeremy in his heart of hearts is a Brexiter and Keir Starmer at that point was passionately pro-European.”

Pressed on whether Mr Corbyn really wanted out of the EU, she said: “Yes, I’ve known Jeremy a long time.

“Remember in the 80s, when both of us were starting out in the party, Tony Benn, who was a huge hero to all of us, and a hero to the Labour Party grassroots, he was anti-EU.

“He saw it as a conspiracy of business people and so on. So, that was the common view on the left in the 80s. And I think it’s the view that Jeremy still held.

“But Jeremy has always been about uniting the party, he knew most party members were pro-European. But himself, I would say, deep down he was a Brexiter.”

Asked if Mr Corbyn voted to Leave, Ms Abbott hesitated before saying: “Oh, he would have voted Remain because that was the policy of the party.”