Image copyright Sun on Sunday

Lord Sewel is facing a police inquiry after quitting as House of Lords deputy speaker over a video allegedly showing him taking drugs with prostitutes.

Lords Speaker Baroness D'Souza said he had also quit as chairman of the Lords privileges and conduct committee in the wake of the Sun on Sunday's story.

The footage showed him snorting powder from a woman's breasts with a £5 note.

Baroness D'Souza said his behaviour was "shocking and unacceptable" and that she was referring him to the police.

"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," she said.

"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."

In the footage, Lord Sewel, who is married, also discusses the Lords' allowances system.

The peer is yet to comment on the claims.

Image caption Lord Sewel was chairman of committees in the Lords

As chairman of committees, the crossbench peer also chaired the privileges and conduct committee, and was responsible for enforcing standards in the Lords.

The role, which comes with an £84,500 salary, meant he was in charge of proceedings when the Lords considered a bill at committee stage, and was automatically made a deputy speaker.

Biography

Name: John Buttifant Sewel

Age: 69

Title: Lord Sewel, of Gilcomstoun in Aberdeen

Educated at Durham and Aberdeen universities

Worked as a lecturer at Aberdeen University

Joined the House of Lords in 1996

Lords career: Parliamentary under Secretary of State, Scottish Office, 1997-1999, opposition Scotland spokesman 2010, elected chairman of committees in 2012

UK representative to Nato Parliamentary Assembly, 1999-2002

Lord Sewel served as a minister in the Scotland office under Tony Blair's Labour government.

The Sewel convention, which applies to the relationship between Westminster and the Scottish government, is named after him.

He has been a member of the Lords since 1996, and is a former senior vice principal of the University of Aberdeen.

In a recent blog for the Huffington Post, he said the Lords had taken "major steps" to "protect its reputation and punish misconduct by its members".

He highlighted the new power of peers to suspend for any length of time or expel a member who had misbehaved.

Media playback is unsupported on your device Media caption MP John Mann: "Lord Sewel has no choice but to resign from the House of Lords"

Labour MP John Mann called for Lord Sewel to resign from the House of Lords.

He said: "When it comes to conduct the House of Lords has been a law unto itself and now we have the chairman of the conduct committee in the House of Lords, the number two figure in the House of Lords, caught in this scandal.

"It's absolutely shocking and he needs to go."