Now it can be told, as they used to say in old Fleet Street. Five happy years have elapsed since I was a member of the parliamentary lobby, so I am no longer bound by the rule of omerta. Therefore, I can tell the truth about how political journalism works and explain the hypocrisy behind Alastair Campbell's charge that the BBC's defence correspondent Andrew Gilligan relied on one source for his story that the government's dossier on Iraq was "sexed up".
Sources are important, not just because Campbell says so, but because that's where the stories come from. Sources have to be nurtured, fed and watered, and given the occasional ego massage. It takes a long time to find a really good source, but only one reckless move to lose him (and it usually is a him). Every day, more than 200 lobby correspondents sweep the beach at Westminster for stories. I don't mean the stuff from Tory Central Office that spews out of the fax, or the self-important ranting of backbenchers. Those are not real stories.
Real stories are what the politicians don't want you to print: the secret of Peter Mandelson's home loan; the £1m donation to Labour from the Formula One boss, Bernie Ecclestone; or Cheriegate. These stories are initially denied, then denigrated, and finally admitted under a gradual process of disclosure. Rule number one: don't let the bastards know how much you know, until you have to.
To get real stories, you need a source. And contrary to what the Prime Minister says, one source is good enough - if he is good enough. Most lobby correspondents have only one source; indeed, all too many have none at all. In his scribbling days at the Daily Mirror and Today, Campbell had only one source - Neil Kinnock, who, usefully, was leader of the Labour Party.
Let me come clean. During my long stint as labour editor of the Times, Lawrence Daly, general secretary of the National Union of Mineworkers, was my source. He gave me documents from the TUC, and I filed my copy from his office in the Euston Road, usually over a large brandy. The Daily Mirror's source was then Cyril Plant, the taxmen's leader, who passed over not only the documents but also an accurate shorthand note of TUC general council meetings.
When I moved into political reporting, Charlie Whelan became my source. I knew him as a spin-doctor with the engineering union AEEU. He consulted me (presumably among others) when headhunted by new Labour. I urged him to accept, not appreciating what a gold mine he would prove. I spoke to him every day, often several times. I fed him at the same table in the Commons press gallery dining room every week. Sometimes, it was a twobl (a two-bottle lunch) or even a threebl. He always had copy, whether it was Gordon Brown's idea for a 10p rate of income tax, or the sinking of the royal yacht.
I was then political correspondent of the Independent on Sunday. Successive editors knew of this arrangement, but in the interests of political theatre, Charlie was always "Source A". If I mentioned his code name, they knew the story was kosher. For instance, he told me about the Chancellor's decision not to hold a referendum on the euro during the first parliament two weeks before he gave the story to the Times on his mobile phone outside the Red Lion pub in Westminster - an event that has now gone down in political history. The IoS buried it in the business section, where nobody read it, proving that the system does not always work. However, I had the pleasure of humiliating the Sunday Telegraph, which ran completely the opposite story.
Your source has to be absolutely reliable. He has to tell you everything, not just what he wants you to hear. So he will not normally be a politician. More likely, he will be a spin-doctor or political adviser or some other apparatchik who is in the loop, but not dependent on the politicians for his future.
Forget Peter Mandelson. Journalists much prefer sources such as Harry Fletcher of the probation officers' union, who has fed generations of home affairs correspondents with stories. Yet few outside the media would know his name.
By constantly reiterating that Gilligan had "only" one source for his story, Campbell hopes to convince the public that the story was false. Few political journalists will expose this for the eyewash it is because they are reluctant to admit that they, too, rely on single sources. I do not know Gilligan, and have never met him. But my sixth sense as a reporter tells me that he has a real source, high on the Whelan scale. It doesn't matter if he met him in a pub, or even a brothel; Campbell used to meet contacts in pubs before he gave up the drink. What matters is not the setting, but the credibility of the source. A real story must satisfy three tests. Is it newsworthy? Is it credible? Is my informant trustworthy? By those criteria, it seems to me that Gilligan had a real story, and had a duty to publish. I believe him. Ergo, I do not believe Campbell.
There is a further point. Campbell knows that Gilligan cannot name his source, and cannot be required to disclose it to MPs. Disclosure would ruin him. So Campbell can rubbish Gilligan and his source and his source's story, secure in the knowledge that the Beeb cannot come totally clean. The Ministry of Defence must have known this also, when it tried to flush out Gilligan's source by offering to name an official who had met Gilligan if the BBC would simultaneously identify that official as the deep throat. This was obviously an attempt to discredit Gilligan and destroy the source pour encourager les autres. These are testing times for sources. New Labour will stop at nothing to crush them.
But let us not forget that the government had only one source for its allegation that Iraq could launch chemical and biological weapons within 45 minutes. Yet the government's position is that its sole source, equally anonymous, must be regarded as credible, while Gilligan's must not. Ministers cannot have it both ways. What's source for the goose is source for the gander.
Paul Routledge is chief political commentator for the Daily Mirror. His normal diary for the NS returns next week