Jonathan Ashworth says he's "saddened" after a Conservative activist he considered a friend leaked a 'wind-up' phone call to a Tory website.
The Shadow Health Secretary said he was 'joshing' when he made comments about Jeremy Corbyn and Labour's chances in the election, in a bid to lull friend Grieg Barker into complacency.
He told the BBC: "I was having a bit of banter with a Tory friend of mine - at least I thought he was a friend - a Tory activist called Greig Baker.
"I was having a bit of banter with him because he was saying, "Oh the Tories are going to lose" and I was saying "no you're going to be fine." - you know, joshing as friends do.
"He's only gone and leaked it all to a website and he's selectively leaked it.
"And I thought he was a friend, Greig Baker, and obviously he's not."
He added: "It's a bit like when you're saying to your mate who's a fan of a rival football team - 'Don't worry, your team's going to win.'
"You're trying to sort of unnecessarily boost their ego and make them complacent."
During the phone call, published on the Guido Fawkes website, Mr Ashworth played down Labour's chances of winning Thursday's election.
He also suggested it was a mistake to make Jeremy Corbyn leader - and anti-Corbyn forces in the party had 'f****d it up' in trying to remove him too early."
And he said there was little to worry about in claims Jeremy Corbyn is a security risk, because if he were the Number 10 machine "will pretty quickly move to safeguard security."
Speaking to the BBC's Victoria Derbyshire, Mr Ashworth added: "Of course I said it, but I'm winding him up. It's banter.
"I'm just saddened that a friend that I spent 3 weeks going round America with 15 years ago has done that because he's a Tory activist."
