A Republican senator issued a humiliating apology yesterday after his telephone number appeared in the phone records of the so-called “DC Madam”, making him the first member of Congress to become ensnared in a growing Washington sex scandal.

David Vitter, a conservative and staunch family values advocate, admitted that his telephone details appeared on a list of 13,000 numbers posted on the internet by Deborah Jeane Palfrey.

She is accused by federal prosecutors of running a prostitution ring that catered for Washington’s power elite.

Ms Palfrey’s decision to release on her website all her phone records covering the seven years up to August 2006 – the list has no names – has sparked frenzied speculation in Washington about who else might be involved.

Ms Palfrey, 51, faces charges of running a prostitution ring in Washington that made more than $2 million (£988,000) over 13 years.

She said she was posting the records “to thwart any possible distorted version and to ensure the integrity of the information”.

When a partial list of numbers was passed by Ms Palfrey to the ABC network in May, Randall Tobias, a deputy to the Secretary of State Condoleezza Rice, abruptly lost his job. He claimed he had used the escort service, Pamela Martin and Associates, for massage, and not sex.

ABC said in May that it had also found telephone links to prominent business executives, Nasa officials and at least five military officers. Another official linked to the telephone list is Harlan Ullman, the military academic who devised the “shock and awe” bombing strategy used in the Iraq invasion. He has said that Ms Palfrey’s accusation “doesn’t deserve the dignity of a response”.

Mr Vitter, who is married with four children, said he used the escort service before becoming a senator.

He said in a statement: “This was a very serious sin for which I am, of course, completely responsible. Several years ago, I asked for and received forgiveness from God and my wife in confession and marriage counselling. Out of respect for my family, I will keep my discussion of the matter there – with God and them. But I certainly offer my deep and sincere apologies to all I have disappointed and let down in any way.”

Mr Vitter, 46, is a solid Louisiana conservative who opposes gay marriage and abortion. A Harvard graduate and former Rhodes Scholar at Oxford, he was elected to the House of Representatives in 1999.

He filled the seat vacated by the disgraced Bob Livingston, who was about to become House Speaker at the height of Bill Clinton’s impeachment over the Monica Lewinsky scandal when he was forced to reveal that he had cheated on his wife.

Mr Vitter, when he ran for the Senate in 2004, faced accusations of an affair with a prostitute in the French Quarter of New Orleans, which he denied.

Asked several years ago how forgiving she would be if her husband was as unfaithful as Mr Livingston or Mr Clinton, Mr Vitter’s wife, Wendy, said: “I’m a lot more more like Lorena Bobbitt than Hillary [Clinton]” – a reference to the woman who in 1993 cut of her husband’s penis with a kitchen knife.

“If he does something like that, I’m walking away with one thing, and it’s not alimony, trust me. I think fear is a very good motivating factor for a marriage.”

Ms Palfrey claims that her service was legal and did not provide sex, only erotic role-playing. She says she wants to reveal previous clients to force them to testify to that effect.

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