The Deputy Speaker of Britain's House of Lords has resigned after a national newspaper published video of him apparently taking drugs with prostitutes.
Baron John Sewel stepped down from his post after the revelations appeared in The Sun On Sunday.
The peer, who was once a key ally of Tony Blair, was in charge of upholding standards in the Lords.
In a statement to Sky News, Lord Sewel said: "I confirm that I have been in touch with the Lord Speaker and have informed her of my resignation as Deputy Speaker and Chairman of Committees."
The Lords Speaker, Baroness D'Souza, said Lord Sewel's behaviour was "shocking and unacceptable."
She said she was now referring him to the Metropolitan Police for investigation.
In a statement she said: "Today's revelations about the behaviour of Lord Sewel are both shocking and unacceptable.
"Lord Sewel has this morning resigned as Chairman of Committees.
"The House of Lords will continue to uphold standards in public life and will not tolerate departure from these standards.
"These serious allegations will be referred to the House of Lords Commissioner for Standards and the Metropolitan Police for investigation as a matter of urgency."
The Sun On Sunday published video and photographs which it said showed 69-year-old Lord Sewel taking drugs with prostitutes at his flat in Dolphin Square, London.
It said the footage was filmed last week.
Lord Sewel was appointed a junior Scotland minister following Mr Blair's first election victory in 1997.
The married father-of-four is a former vice-principal of Aberdeen University and was leader of Aberdeen district council in the late 1970s.
