Tony Blair made an appeal for the media to stop prying into Mr Davies's private life, as the Government braced itself for more revelations about the "bizarre" events on Clapham Common that led to the former minister's downfall.
Looking tired and red-eyed, Mr Davies said: "It was a moment of madness for which I have subsequently paid a very, very heavy price and I am deeply sorry. I bitterly regret it."
After a week that has left his political career in ruins, and caused turmoil in the Labour Party as it tries to find a replacement in Wales, Mr Davies continued to deny that either sex or drugs were involved in his picking up a man in his 50s and two accomplices, a man and a woman, to travel to Brixton, south London, where he was robbed of his car, telephone, and wallet.
He said he later realised he had acted foolishly by not recognising the warning signs after engaging in conversation with the stranger.
He told how two other individuals later held a knife at his throat while they went through his wallet and stole personal effects, including his mobile telephone. The robbers also threatened to set fire to his car unless he got money for them.
Police last night charged an unemployed man, Donald Fearon, with theft of the MP's Ford Granada car and its contents in Dray Gardens, Brixton, on Monday night. Mr Fearon, 38, of no fixed address, will appear before magistrates at Camberwell Green today.
Rumours were circulating at Westminster about further disclosures this weekend, and the Government was seeking to limit the damage. However, the timing could not be worse, with Jack Straw, the Home Secretary, preparing to unveil a government Green Paper on Wednesday on the family.
The former secretary of state for Wales, who has been at a secret address with his wife and 13-year-old daughter since being forced to resign from the Cabinet on Tuesday, admitted the circumstances leading up to his robbery at knifepoint were "bizarre", and he had made a "gross error of judgement".
Mr Davies said he was still suffering the effects of shock and trauma "after a pretty horrific experience" during the robbery. He refused to discuss questions about his private life but said: "I have a very long- term, loving, stable relationship with my wife, who has been marvellously supportive of me this week."
It was too early to discuss his political career, Mr Davies said, but he would be staying on as an MP and concentrating on rebuilding his relationship with his constituents in Caerphilly, who had deluged him with messages of support.
Mr Davies, who was speaking in south Wales, denied that the Prime Minister and other senior Labour figures had pressurised him into resigning from the Cabinet and standing down as Labour's prospective leader of the Welsh Assembly.
"Tony Blair was very, very supportive and understanding, and I am deeply grateful for the way he has handled this matter as far as I am concerned," Mr Davies said.
Mr Blair yesterday appealed for Mr Davies to be left in peace. "This has been a week of very great personal agony and tragedy for Ron Davies," the Prime Minister said.
"He has paid a very heavy price for what's happened and I know a lot of people in Wales will respect enormously the way he has come through this. I hope he is allowed to rebuild his life with his own family."
There were allegations yesterday that Mr Davies was forced to resign because he changed his story after initially telling police that he had been the victim of a car-jacking outside his home.
But a Downing Street spokesman said: "The Prime Minister is not aware of any other version of events."
Mr Davies's resignation from the top Labour post in Wales was clearly a relief for Downing Street. Friends of the former secretary of state said Mr Blair, who was in daily contact with his colleague, did not need to push him to go; he knew what was required.
The consequences of the affair had all the signs yesterday of turning into a public relations disaster for the Government as the search began for a replacement candidate to lead the Welsh Assembly. Alun Michael, Mr Davies's replacement as Welsh Secretary, showed deep reluctance to be drawn into putting his name forward.
The executive of the Welsh Labour Party will be under pressure on Monday to agree a quick solution, but Rhodri Morgan, Mr Davies's defeated challenger, made it clear he wanted a rerun of the election for the Welsh leadership.
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