Mystery of the think tank that keeps its thoughts to itself

It is the £1 political think tank that lists a Hertfordshire solicitor as its sole director; a talking-shop with no one to speak for it; a body dedicated to progressive policies that publishes nothing and holds no conferences. It doesn't even have a website.

But the Progressive Policies Forum (PPF) was one of the most important contributors to the ultimately unsuccessful campaign to install Peter Hain as deputy leader of the Labour Party. And it might just turn out to be the thing that ends his political career.

A senior organiser on the campaign of one of Hain's rivals for the deputy leadership confirmed last night that raising money during the contest had been "devilishly difficult" – and that they had suspected opponents of bending the rules. No one, however, could have foreseen the unusual route taken by Hain's team to pull in more than £50,000.

PPF documents lodged at Companies House confirm that the organisation is a limited company, but only one shareholder is listed – and it is not anyone recognisable as a Peter Hain aide. Gregory McEwen, a solicitor from Chorleywood, Hertfordshire, holds the single share, worth £1.

Mr McEwen was unavailable for comment last night.

For a think tank set up in December 2006, the PPF has been remarkably quiet, but it now emerges PPF was demonstrating its values in other areas. Amid the fallout from Mr Hain's admission that he had failed to declare some £103,000 in campaign donations last week, it was revealed that almost half of the total came via the PPF. Some £26,000 in donations and an interest-free loan of £25,000 that had been made to PPF were switched to the Hain campaign to meet unpaid bills after the contest.

With leading supporters of Mr Hain's campaign yesterday insisting they had known nothing about the PPF, it was left to its founder, John Underwood, a former Labour director of communications, who ran the finances for Mr Hain's campaign, to claim that all of the donors, including diamond dealer Willie Nagel and businessman Isaac Kaye, were happy with the funding arrangement.

It was not entirely convincing, and Mr Hain failed to expand on the explanation during his brief statement yesterday. Nor did he explain how much he knew about PPF.

He will have to come up with some answers soon, if not to the public, then to the parliamentary authorities and, ultimately, to the Prime Minister himself.