GAO investigation

Who was present at each meeting of the energy task force? What are the names of the professional staff assigned to the task force? Who did the task force members meet, and why and when? What direct and indirect costs were incurred in developing the National Energy Policy?

The White House has refused to hand over records of the government's energy task force, headed by Mr Cheney, arguing that this would stop the administration from getting candid advice from outside experts.

The GAO investigation is quite separate from official inquiries into the collapse of Enron over debt and accounting irregularities, and began as long ago as April 2001.

But interest in the documents has increased as nine Congress inquiries are probing Enron's business practices, the failure of government regulation, and whether the company exercised undue influence over government policy.

In a letter to the White House, Comptroller General David Walker said he "would have strongly preferred to avoid litigation in connection with this matter", but would now file suit in a US District Court.

"This will be the first time that GAO has filed suit to enforce our access rights against a federal official. We hope it is the last time that we will have to do so", Mr Walker wrote.

White House spokesman Ari Fleischer said the government was confident it would win the court case.

Candid advice

The White House is withholding the records of the National Energy Policy Development Group on a point of principle. Surrendering the details of the talks, officials say, would make it impossible for governments to hold private and uninhibited discussions in the future.

Mr Cheney said there were no secrets to hide: "We talked to all kinds of people. I talked to energy companies, I talked to labour members, talked to environmentalists."

Mr Fleischer added the president would "stand for the right of presidents... to receive candid advice without it being turned into a news release".

The GAO counters that "contrary to recent assertions, we are not seeking the minutes of these meetings or related notes of the Vice President's staff".

But critics have accused the government of being too close to industry interests when it formulated its federal energy plan last spring, and the GAO investigation is

Enron and its chief executive Kenneth Lay were generous donors to the election campaign of President George W Bush, although the firm showered money on Senators and Representatives from both parties.

Comptroller General moves in

The man behind the lawsuit is the comptroller general, David Walker, who is in charge of the General Accounting Office.

He has impeccable Republican credentials, and was a volunteer working for the presidential campaign of George Bush Sr.

Despite this partisan background, Mr Walker said his team was ready "to do our job", arguing that the GAO had the right to get the information, because the energy task force was funded by taxpayers.

"In our view, failure to pursue this matter could lead to a pattern of records access denials that would significantly undercut GAO's ability to assist Congress in exercising its legislative and oversight authorities", Mr Walker said in his letter to the White House.