Builder Paul Leatherbarrow’s colleagues listened laughing in the site hut as Radio 4’s World at One interviewed him thinking he was MP Mike Crockart.

The Daily Telegraph revealed that Leatherbarrow went along with the interview because he thought he was speaking to a friend playing a prank.

The father of two, said he was at work on a building site near his home in Middleton, Greater Manchester, when he got a call on his mobile phone from the BBC.

He said: “I thought it was my mates playing a joke on me – they’re always winding me up.

“They said they had a slot on the radio in seven minutes and would I be able to go on?”

Listeners to the World at One heard James Robbins, the presenter, say: “I’m joined now by the Edinburgh West MP, Michael Crockart, who’s a parliamentary aide – a PPS – to the Scottish Secretary, Michael Moore.”

He then asked: “Michael Crockart, are you going to resign over this issue?”

The interviewee replied: “It’s not so much I am going to resign. I am prepared to resign.”

Robbins pressed ahead: “Meaning that you would like to vote against this but feel you can’t, and therefore you will resign in order to do so?”

The “MP” continued: “If I’m backed into a corner, yeah.”

Then, in a bizarre answer which perhaps ought to have alerted the BBC that something was wrong, he added: “I mean the main thing, what was the big problem in the beginning, was the grit bins,” before the line went dead.

Undeterred, Robbins told listeners: “I think we’ve lost Michael Crockart so I’m going to go now to our political correspondent Iain Watson, who’s at Westminster and joins me now.”

Watson proceeded to analyse the bogus interview, saying: “I think, yes, signs of growing cracks. I think we got the significant bit of the conversation, James, where he said ‘I’m prepared to resign.'”

The real MP was forced to issue a denial, saying that the remarks had been made by a “random, unknown man” – although he did in fact resign on Thursday when he voted against the Coalition’s plan to raise fees.

The confusion arose because Leatherbarrow’s mobile phone number was incorrectly listed against Crockart’s name in a directory of MPs’ contact details published by the BBC, copies of which circulate around Westminster.

In its subsequent apology, the BBC insisted: “The usual pre-broadcast questions were asked of the person concerned, who maintained throughout that he was Mr Crockart and appeared credible.”

But Leatherbarrow told the Telegraph that no checks were made, other than asking if he was the MP.

He said: “It’s probably embarrassing for them [the BBC] because they’ve claimed they did all these checks but they didn’t. They just asked if I was Mike Crockart and if I was willing to go on the radio and I said I was.

“Also I’m told that Michael Crockart has a Scottish accent and is a Scottish MP so I’m surprised they didn’t smell a rat.”

Recounting the moment that his voice was broadcast to the nation, he said: “There were about 12 of us in the tea cabin at work. I went outside and my mates put the radio on. I was just told to hold until I heard the presenter asking me a question.

“Then when I answered all my mates were laughing and banging on the window saying ‘It’s you, it’s you.’ I just broke down in laughter at the end.

“I read somewhere that I sounded like a ‘Yorkshireman putting on a squeaky voice’. That was because I was trying to put on a posh accent but I just ended up sounding like I was from Yorkshire.”

The two men’s lives started to converge around six months ago when the BBC printed its contacts directory containing the error.

“At first I would just hang up the phone,” said Leatherbarrow. “But then it happened a few more times and I was convinced it was my mates winding me up because they’re always doing that.

“I went to the dentist once and one of them rang me up putting on this strange accent, saying he was one of the dentists and they had put the wrong kind of filling in my tooth.

“He said I needed to come back to the practice so they could take it out before my teeth would rot. So I went rushing back saying ‘You need to take my filling out – you told me my tooth would fall out.’ They must have thought I was mad.

“Then a couple of weeks ago I got a call asking for Mr Crockart and saying my dinner date was confirmed and did I want pork.

“So I just thought I’d play along with it and said pork would be fine but make sure it’s well done. So I probably need to apologise for ruining Mr Crockart’s dinner too.”

Following the resignation of the real Crockart from the Government’s ranks, Leatherbarrow will also be stepping down as his imposter.

The construction worker said: “The phone has been ringing non-stop since it happened. I’ve had enough now. I just want the quiet life – I don’t like all this fuss. My family is the most important thing to me and they’ve been a bit freaked out by it.

“So I’ve decided to retire. I’ll be changing my phone number as soon as I can. But at least it’s a story to tell the grandchildren.

“I thought it was a bit of fun at first, and if I hadn’t had my mates waving and banging on the window then I could have kept it going longer.

“I even got to mention grit in the interview, because my mate is always going on about there not being enough grit on the roads.

“It’s probably quite easy being a politician. You just come out with stuff that doesn’t really mean anything.

“My mates will make fun of me saying I made him resign, but it was nothing to do with me – he would have done it for his own reasons.

“I didn’t mean any harm and I hope I haven’t offended Mr Crockart. I know it’s a serious issue but I just thought it was a wind up.

“I did see the student riots on the TV and I do feel some sympathy for the students, but it’s difficult for everyone at the moment. Some of my mates are out of work.”