The Republican National Committee and chairman of George W. Bush’s 2004 campaign have been ordered to preserve all e-mails related to White House business because they might be relevant to multiple congressional investigations.

Henry Waxman, Democratic chairman of the House oversight committee, said in letters to the RNC and the former head of the 2004 Bush/Cheney campaign that congressional investigations revealed that White House officials had used non-governmental e-mail accounts controlled by the RNC and the 2004 campaign for business.

In some cases uncovered in the probe involving Jack Abramoff, the Republican lobbyist jailed for corruption, White House officials used the accounts to avoid creating a record of communication.

In one instance, Mr Abramoff, who is serving a 70-month sentence on corruption charges, sent an e-mail to Susan Ralston, executive assistant to Karl Rove, the president’s chief political strategist, on her RNC account about a gaming-related decision by the department of the interior.

When the e-mail was forwarded to another official in the White House e-mail system, Mr Abramoff was warned by an associate who said the official “said it is better not to put this stuff in writing in their e-mail system because it might actually limit what they can do to help us”.

Mr Abramoff responded: “Dammit. It was sent to Susan on her RNC pager and was not supposed to go into the WH system.”

”We are reviewing it and taking appropriate action,” the RNC said yesterday.

In another instance, the congressional investigation into the firing of eight US attorneys has also revealed an e-mail exchange in which J. Scott Jennings, the special assistant to the president and deputy director of public affairs, used an RNC e-mail account to communicate with Kyle Sampson, the former chief of staff to Attorney General Alberto Gonzales who is due to testify about the firing on Thursday.

Bruce Fein, a legal scholar, said Mr Waxman was putting the RNC on notice and that any future destruction of e-mails could bring an obstruction charge.

The RNC said: “We are reviewing it and taking appropriate action.”

Separately, an aide to Mr Gonzales on Monday invoked her constitutional right against self-incrimination and refused to testify before a Senate panel investigating the firing of eight prosecutors.

Monica Goodling, who was involved in the firings, said: ”I have decided to follow my lawyer’s advice and respectfully invoke my constitutional right because the …circumstances present a perilous environment in which to testify.”

Copyright The Financial Times Limited 2007