The bank clerk recognised the gravelly Scots accent instantly. He had heard this man on TV, lecturing the people on the value of prudence with a purpose. He imagined the Chancellor's jaw jutting on the other end of the line as he checked his account details. Yes, thought the clerk, a man so careful with his own money could certainly be trusted with other people's.
Except it wasn't Gordon Brown. Welcome to the weird world in which everyone from hard-up actors and private eyes to ex-coppers and former telephone engineers sells information difficult or impossible to obtain by fair means rather than foul.
Benji the Binman is a rare example of Fleet Street's Dickensian underworld briefly exposed here to daylight. The professional muckraker - who, in his search for the discarded memos and letters of the famous, probably takes more rubbish off the streets of London than Westminster, Islington, Camden and Kensington councils combined - has been blamed for the leaking of memos from Tony Blair and his polling guru, Philip Gould. Few, if any, public prints could honestly claim that they have never used, directly or indirectly, one of his documents.
Politicians and civil servants tend to look for Deep Throats. Their nightmares also encompass computer hackers, telephone taps, scanners, bugs and devices able to pick up conversations from the vibrations of a window-pane. But Benji's example shows that, often, it's not so much All the President's Men as Steptoe and Son. Newspapers frequently use perfectly mundane methods of obtaining information.
Meet Gavin. A former thespian who lives in (let's say) Sussex, he now makes a lot more money than he did treading the boards. A brilliant mimic, his voices are superb. So good, in fact, that if he rang, you would be unlikely to know if it was whoever he was that day or just plain old Gavin.
Say hello to Jonathan. Those in the know say that he's not quite as convincing as Gavin, but he can be pretty convincing as a lawyer, accountant or assistant to a high-profile public figure.
The scale of fees varies from customer to customer, but one newspaper pays £1,000 a go to stand up rumours or obtain that vital piece of information needed to get a story off the ground. Bank and mortgage arrangements, credit card statements and itemised phone bills: Gavin and Jonathan can get them. These boys do their homework, memorising dates of birth, maiden names, addresses and anything else that a reasonably well-trained or mildly suspicious employee might ask. Tricks of the trade include ringing at lunchtime when, with half the staff away and the other half looking forward to a break, a person's guard is often down.
The experts rarely go in for the kill first time. The initial call may be no more than a check that another standing order can be fixed. But that call is logged and, when the second is put through, Gavin or Jonathan need only mention the date of the previous call and the unwitting accomplice is immediately at his or her ease when it comes up on the computer screen.
Want an "ex-d", an ex-directory number? £100 will do nicely. BT has made tens of thousands of engineers redundant, and a few of them have taken the codes needed to get numbers when "repairing" phone lines.
One newspaper boasts that it can get private medical records from a source if they are stored on computer and, in certain circumstances, even if they are paper files.
Then there are the private investigators, ex-coppers and serving officers who, as well as sometimes making it difficult to distinguish which is which, are happy to lend a helping hand if their palms are crossed not with silver, but with large bundles of notes. Not for nothing is the police national computer considered one of the leakiest. This mob has its own canteen culture, based on favours and rewards, which sees information bought and sold in a manner that the Home Secretary, Jack Straw, would not approve of.
So sensitive are some of these contacts that they are paid in cash to keep them off the books and thus avoid storing incriminating evidence. The money is handed over in the obligatory brown envelope, perhaps to "buy the wife a present" or "enjoy a drink". The newspapers need "deniability": an editor should be able to profess innocence and keep a straight face. So those who ring Gavin, Jonathan and the rest ask for help, not for crimes to be committed.
Who rang the Royal Bank of Scotland's branch on London's Strand, claiming to represent Michael Ashcroft, to discover the exact amount that the billionaire Tory treasurer was spending to keep the Conservative Party afloat? Who made the phone calls to the Inland Revenue on 9 June and 23 June about the tax bills of Labour's millionaire fundraiser Lord (Michael) Levy, just before it was revealed that he paid only £5,000 in 1998-99?
And who was that man, sounding so much like Gordon Brown, who rang the bank clerk shortly before details of the Chancellor's Abbey National mortgage and his purchase of a London flat from the debris of Robert Maxwell's empire were presented to an unexpecting (and largely unexcited) nation?
Ashcroft, Levy and Brown will probably never know. And Rory Bremner has more competition than he may realise.
The writer now works for the Guardian, but in the past has worked for tabloid newspapers