More details have emerged about how confidential information on MPs' expenses might have found its way into the hands of journalists.

The information, which has led to a string of articles that exposed how elected representatives made a series of questionable claims, was purchased by the Daily Telegraph from a seller who offered the data to other Fleet Street newspapers.

This data includes a hard drive containing expense claims made by MPs over the last five years, together with two million supporting documents including copies of expense claim forms, The Guardian reports. How someone managed to smuggle data from a classified machine onto a (presumably) external hard disc, much less smuggle out enough supporting paperwork to fill a van from the Palace of Westminster, remains unclear.

The circumstances suggest an insider, possibly one who works in the fees office, is behind the leak. The subsequent shenanigans make for a piece of political intrigue with shades of the thriller State of Play, with large hints of the caustic Westminster comedy The Thick of It.

On 18 March three journalists from The Times reportedly met with a broker to discuss the sale of the data at the offices of a public relations firm. An asking price of £300,000 - £250,000 for the data, £50,000 in analysis fees - was put on the table, along with a promise to provide legal indemnity during the 30 minute meeting, which involved discussion of snippets of the data on offer. The Times turned down the deal.

The businessman brokering the deal was identified by the Wall Street Journal, The Sunday Times (here) and the Mail on Sunday (here) as John Wick, a former SAS major and current director of risk management and security firm International Security Solutions Limited (ISSL). Henry Gewanter, managing director of PR firm Positive Profile, reportedly assisted Wick.

El Reg spoke to Gewanter, who declined to comment. Staff at ISSL said that Wick was out of the office and unavailable for comment. We've left a message and will update this story as and when Wick gets in touch.

ISSL specialises in "corporate risk management" which, according to case studies on its site, involves everything from running kidnap and ransom response to tracking suspected internal fraud for a Caribbean telecoms firm, and defending an unnamed electronics firm against charges of violating UN sanctions.

In late March the Sunday Express ran an exclusive that home secretary Jacqui Smith's husband paid to watch a couple of X-rated films, the cost of which was subsequently claimed back on expenses. The data used to stand up this story apparently came from the same source.

Days after this scoop, The Sun was offered a portion of the expense claims information, but editor Rebekah Wade walked away from the deal after first offering only £20,000 for the information, a decision she reportedly regrets.

The seller next approached The Telegraph, which agreed an undisclosed deal and begin printing a series of stories. Whoever sold the information could find it hard to argue that they acted in the public interest after attempting to profit by auctioning the information around Fleet Street.

Intermediaries in the deal might also be implicated. Should police press on with an investigation, then editors at both the Sunday Express and the Daily Telegraph could also have reason to worry.

Fleet Street insiders describe the deal as amateurish, mainly because neither the Daily Mail nor the Mail on Sunday, the two papers likely to pay the highest fees, were offered the scoop. ®