When I broke down in my midlife crisis car in remotest Kent just before Christmas, a battered white van pulled up on the far carriageway. To help, I thought. But when the driver got out he started taking pictures with a long-lens camera. He came closer to get better shots and I swore at him. Then he offered me a lift the last few miles to my destination. I suspected his motives and swore at him some more. (I'm not entirely sympathetic towards paparazzi.) Then I realised I couldn't get a taxi and was late. So I had to accept the lift.

He turned out to be an ex-News of the World investigative journalist and paparazzo, now running a pub in Dover. He still kept his camera in the car's glove box for just this kind of happy accident.

More than that, he was Paul McMullan, one of two ex-NoW hacks who had blown the whistle (in the Guardian and on Channel 4's Dispatches) on the full extent of phone-hacking at the paper, particularly under its former editor Andy Coulson. This was interesting, as I had been a victim - a fact he confirmed as we drove along. He also had an unusual defence of the practice: that phone-hacking was a price you had to pay for living in a free society. I asked how that worked exactly, but we ran out of time, and next thing we had arrived and he was asking me if I would pose for a photo with him, "not for publication, just for the wall of the pub".

I agreed and the picture duly appeared in the Mail on Sunday that weekend with his creative version of the encounter. He had asked me to drop into his pub some time. So when, some months later, Jemima asked me to write a piece for this paper, it occurred to me it might be interesting to take him up on his invitation.

I wanted to hear more about phone-hacking and the whole business of tabloid journalism. It occurred to me just to interview him straight, as he has, after all, been a whistleblower. But then I thought I might possibly get more, and it might be more fun, if I secretly taped him, The bugger bugged, as it were. Here are some excerpts from our conversation.

Me So, how's the whistleblowing going?

Him I'm trying to get a book published. I sent it off to a publisher who immediately accepted it and then it got legal and they said, "This is never going to get published."

Me Why? Because it accuses too many people of crime?

Him Yes, as I said to the parliamentary commission, Coulson knew all about it and regularly ordered it . . . He [Coulson] rose quickly to the top; he wanted to cover his tracks all the time. So he wouldn't just write a story about a celeb who'd done something. He'd want to make sure they could never sue, so he wanted us to hear the celeb like you on tape saying, "Hello, darling, we had lovely sex last night." So that's on tape - OK, we've got that and so we can publish . . . Historically, the way it went was, in the early days of mobiles, we all had analogue mobiles and that was an absolute joy. You know, you just . . . sat outside Buckingham Palace with a £59 scanner you bought at Argos and get Prince Charles and everything he said.

Me Is that how the Squidgy tapes [of Diana's phone conversations] came out? Which was put down to radio hams, but was in fact . . .

Him Paps in the back of a van, yes . . . I mean, politicians were dropping like flies in the Nineties because it was so easy to get stuff on them. And, obviously, less easy to justify is celebrities. But yes.

Me And . . . it wasn't just the News of the World. It was , you know - the Mail?

Him Oh absolutely, yeah. When I went freelance in 2004 the biggest payers - you'd have thought it would be the NoW, but actually it was the Daily Mail. If I take a good picture, the first person I go to is - such as in your case - the Mail on Sunday. Did you see that story? The picture of you, breaking down . . . I ought to thank you for that. I got £3,000. Whooo!

Me But would they [the Mail] buy a phone-hacked story?

Him For about four or five years they've absolutely been cleaner than clean. And before that they weren't. They were as dirty as anyone . . . They had the most money.

Me So everyone knew? I mean, would Rebekah Wade have known all this stuff was going on?

Him Good question. You're not taping, are you?

Me [slightly shrill voice] No.

Him Well, yeah. Clearly she . . . took over the job of [a journalist] who had a scanner who was trying to sell it to members of his own department. But it wasn't a big crime. [NB: Rebekah Brooks has always denied any knowledge of phone-hacking. The current police investigation is into events that took place after her editorship of the News of the World.]

It started off as fun - you know, it wasn't against the law, so why wouldn't you? And it was only because the MPs who were fiddling their expenses and being generally corrupt kept getting caught so much they changed the law in 2001 to make it illegal to buy and sell a digital scanner. So all we were left with was - you know - finding a blag to get your mobile [records] out of someone at Vodafone. Or, when someone's got it, other people swap things for it.

Me So they all knew? Wade probably knew all about it all?

Him [...] Cameron must have known - that's the bigger scandal. He had to jump into bed with Murdoch as everyone had, starting with Thatcher in the Seventies . . . Tony Blair . . . [tape is hard to hear here] Maggie openly courted Murdoch, saying, you know, "Please support me." So when Cameron, when it came his turn to go to Murdoch via Rebekah Wade . . . Cameron went horse riding regularly with Rebekah. I know, because as well as doorstepping celebrities, I've also doorstepped my ex-boss by hiding in the bushes, waiting for her to come past with Cameron on a horse . . . before the election to show that - you know - Murdoch was backing Cameron.

Me What happened to that story?

Him The Guardian paid for me to do it and I stepped in it and missed them, basically. They'd gone past - not as good as having a picture.

Me Do you think Murdoch knew about phone-hacking?

Him Errr, possibly not. He's a funny bloke given that he owns the Sun and the Screws . . . quite puritanical. Sorry to talk about Divine Brown, but when that came out . . . Murdoch was furious: "What are you putting that on our front page for? You're bringing down the tone of our papers." [Indicating himself] That's what we do over here.

Me Well, it's also because it was his film I was about to come out in.

Him Oh. I see.

Me Yeah. It was a Fox film.

[A pause here while we chat to other customers, and then - ]

Him So anyway, let me finish my story.

Me Murdoch, yes . . .

Him So I was sent to do a feature on Moulin Rouge! at Cannes, which was a great send anyway. Basically my brief was to see who Nicole Kidman was shagging - what she was doing, poking through her bins and get some stuff on her. So Murdoch's paying her five million quid to big up the French and at the same time paying me £5.50 to fuck her up . . . So all hail the master. We're just pawns in his game. How perverse is that?

Me Wow. You reckon he never knew about it?

Him [pause] I don't even think he really worried himself too much about it.

Me What's his son called?

Him James. They're all mates together. They all go horse riding. You've got Jeremy Clarkson lives here [in Oxfordshire]. Cameron lives here, and Rebekah Wade is married to Brooks's son [the former racehorse trainer Charlie Brooks]. Cameron gets dressed up as the Stig to go to Clarkson's 50th birthday party [NB: it was actually to record a video message for the party]. Is that demeaning for a prime minister? It should be the other way round, shouldn't it? So basically, Cameron is very much in debt to Rebekah Wade for helping him not quite win the election . . . So that was my submission to parliament - that Cameron's either a liar or an idiot.

Me But don't you think that all these prime ministers deliberately try to get the police to drag their feet about investigating the whole [phone-hacking] thing because they don't want to upset Murdoch?

Him Yeah. There's that . . . You also work a lot with policemen as well . . . One of the early stories was [and here he names a much-loved TV actress in her sixties] used to be a street walker - whether or not she was, but that's the tip.

Me and Chum MLTVA?!

Me I can't believe it. Oh no!

Chum Really??

Him Yeah. Well, not now . . .

Chum Oh, it'd be so much better if it was now.

Him So I asked a copper to get his hands on the phone files, but because it's only a caution it's not there any more. So that's the tip . . . it's a policeman ringing up a tabloid reporter and asking him for ten grand because this girl had been cautioned right at the start of his career. And then I ask another policemen to go and check the records . . . So that's happening regularly. So the police don't particularly want to investigate.

Me But do you think they're going to have to now?

Him I mean - 20 per cent of the Met has taken backhanders from tabloid hacks. So why would they want to open up that can of worms? . . . And what's wrong with that, anyway? It doesn't hurt anyone particularly. I mean, it could hurt someone's career - but isn't that the dance with the devil you have to play?

Me Well, I suppose the fact that they're dragging their feet while investigating a mass of phone-hacking - which is a crime - some people would think is a bit depressing about the police.

Him But then - should it be a crime? I mean, scanning never used to be a crime. Why should it be? You're transmitting your thoughts and your voice over the airwaves. How can you not expect someone to just stick up an aerial and listen in?

Me So if someone was on a landline and you had a way of tapping in . . .

Him Much harder to do.

Me But if you could, would you think that was illegal? Do you think that should be illegal?

Him I'd have to say quite possibly, yeah. I'd say that should be illegal.

Me But a mobile phone - a digital phone . . . you'd say it'd be all right to tap that?

Him I'm not sure about that. So we went from a point where anyone could listen in to anything. Like you, me, journalists could listen in to corrupt politicians, and this is why we have a reasonably fair society and a not particularly corrupt or criminal prime minister, whereas other countries have Gaddafi. Do you think it's right the only person with a decent digital scanner these days is the government? Whereas 20 years ago we all had a go? Are you comfortable that the only people who can listen in to you now are - is it MI5 or MI6?

Me I'd rather no one listened in, to be honest. And I might not be alone there. You probably wouldn't want people listening to your conversations.

Him I'm not interesting enough for anyone to want to listen in.

Me Ah . . . I think that was one of the questions asked last week at one of the parliamentary committees. They asked Yates [John Yates, acting deputy commissioner of the Metropolitan Police] if it was true that he thought that the NoW had been hacking the phones of friends and family of those girls who were murdered . . . the Soham murder and the Milly girl [Milly Dowler].

Him Yeah. Yeah. It's more than likely. Yeah . . . It was quite routine. Yeah - friends and family is something that's not as easy to justify as the other things.

Me But celebrities you would justify because they're rich?

Him Yeah. I mean, if you don't like it, you've just got to get off the stage. It'll do wonders.

Me So I should have given up acting?

Him If you live off your image, you can't really complain about someone . . .

Me I live off my acting. Which is different to living off your image.

Him Yeah, but you're still presenting yourself to the public. And if the public didn't know you -

Me They don't give a shit. I got arrested with a hooker and they still came to my films. They don't give a fuck about your public image. They just care about whether you're in an entertaining film or not.

Him That's true . . . I have terrible difficulty with him [points to pap shot of Johnny Depp]. He's really difficult. You know, I was in Venice and he was a nightmare to do because he walks around looking like Michael Jackson. And the punchline was . . . after leading everyone a merry dance the film was shot on an open balcony - I mean, it was like - he was standing there in public.

Me And you don't see the difference between the two situations?

Chum He was actually working at this time? As opposed to having his own private time?

Him You can't hide all the time.

Me So you're saying, if you're Johnny Depp or me, you don't deserve to have a private life?

Him You make so much more money. You know, most people in Dover take home about £200 and struggle.

Me So how much do you think the families of the Milly and Soham girls make?

Him OK, so there are examples that are poor and you can't justify - and that's clearly one of them.

Me I tell you the thing I still don't get - if you think it was all right to do all that stuff, why blow the whistle on it?

Him Errm . . . Right. That's interesting. I actually blew the whistle when a friend of mine at the Guardian kept hassling me for an interview. I said, "Well if you put the name of the Castle [his pub] on the front page of the Guardian, I'll do anything you like." So that's how it started.

Me So, have you been leant on by the NoW, News International, since you blew the whistle?

Him No, they've kept their distance. I mean, there's people who have much better records - my records are non-existent. There are people who actually have tapes and transcripts they did for Andy Coulson.

Me And where are these tapes and transcripts? Do you think they've been destroyed?

Him No, I'm sure they're saving them till they retire.

Me So did you personally ever listen to my voice messages?

Him No, I didn't personally ever listen to your voice messages. I did quite a lot of stories on you, though. You were a very good earner at times.

Those are the highlights. As I drove home past the white cliffs, I thought it was interesting - apart from the fact that Paul hates people like me, and I hate people like him, we got on quite well. And, absurdly, I felt a bit guilty for recording him.

And he does have a very nice pub. The Castle Inn, Dover, for the record. There are rooms available, too. He asked me if I'd like to sample the honeymoon suite some time: "I can guarantee your privacy."

-- Listen to the audio now --