The results of his investigation into the three businesses, two of which were subsequently sold on by their managements at a vast profit, would almost certainly have made for uncomfortable reading had they been made public before polling day.
In the case of one of the companies, Porterbrook, the management and City financial institutions made a pounds 400m profit on the resale of the business to Stagecoach. Another of the leasing companies, Eversholt, was sold on to a subsidiary of the banking group HSBC last month, netting a pounds 316m profit for its managers and venture capital backers.
Sandy Andersen, the managing director of Porterbrook, made an estimated pounds 46m out of the Stagecoach takeover while his opposite number at Eversholt, Andrew Jukes, is estimated to have made almost pounds 16m.
Whitehall sources said that the NAO, which is an entirely independent body reporting direct to Parliament, had not been under any political pressure to delay publication. Sources said that Sir John's report was "some weeks" away from completion. Once an election is called he is not able to publish any reports. Since this could happen in the next fortnight, even though the country may not go to the polls until 1 May, it rules out publication while the present Government is still in office.