London - Police with sniffer dogs and a battering ram raided Lord Sewel's flat in central London on Monday night after he was filmed apparently taking cocaine in the company of prostitutes.
Officers emerged from the apartment carrying large bags of evidence following a three-hour fingertip search of the premises.
The Metropolitan Police said it was looking into “allegations of drug-related offences involving a member of the House of Lords”.
Earlier, Lord Sewel announced that he was taking a “leave of absence” from the House of Lords, although he stopped short of resigning from the upper house.
The episode, which followed a succession of lurid headlines and photographs in The Sun, has prompted fresh calls for reform of the Lords.
Lord Sewel had already stepped down as Deputy Speaker of the Lords and as chairman of its Privileges and Conduct Committee and Labour has suspended his party membership.
But he faced demands to resign from Parliament altogether, with David Cameron saying there were questions about his fitness to sit in the Lords following the “very serious” allegations.
The former minister, who sits as a crossbencher, said he was taking a leave of absence from the upper house, which means he has to give three months' notice if he wants to resume his seat.
He will not be entitled to claim the daily attendance allowance of up to £300 or to use the facilities of the Lords.
However, his move stops short of resignation and leaves the door open to a possible return.
Lord Sewel told the Clerk of the Parliaments, David Beamish: “I also wish to make clear that in doing so I have no intention of returning to the House in any way until the current investigations have been completed, when in the light of their outcome I will review my long-term position.”
An investigation by the Lords Commissioner for Standards, Paul Kernaghan, was triggered after the Lords Speaker, Baroness D'Souza, asked him to examine Lord Sewel's conduct under rules governing the “integrity” of peers.
That could be the first step in a process which could ultimately lead to his permanent expulsion from the Lords under new rules put in place just 12 days ago.
Lady D'Souza, who has described the peer's behaviour as “shocking and unacceptable”, also reported the allegations to the Metropolitan Police, but the moves in the Lords will be put on hold during any criminal investigation by Scotland Yard.
Lord Brabazon, who preceded him as the chairman of the privileges committee, urged Lord Sewel to step down voluntarily and warned that the investigation into the “ghastly” allegations could be protracted.
The former Commons Speaker, Baroness Boothroyd, said the peer should be “totally embarrassed and ashamed” and had brought the Lords into “some disrepute”. She also said she supported introducing a retirement age for peers.
Lost Lords peers who have strayed
It is only this month that the power to expel peers from the House of Lords permanently came into force.
As a result, its 783 members include several who have brought the institution into disrepute:
Lord Hanningfield (pictured right), the former Tory leader of Essex County Council, was jailed for nine months for false accounting and was temporarily banned from the Lords.
He was banned again after going in to claim his attendance allowance and leaving 20 minutes later.
That ban ended at the election.
The former Conservative peer Lord Taylor of Warwick was jailed for 12 months for falsely claiming more than £11 200 after listing his nephew's home in Oxford as his main residence when he really lived in London.
He was suspended from the Lords for 12 months.
Baroness Uddin (pictured left), formerly a Labour peer, was suspended for 18 months in 2010 and ordered to repay more than £125 000 in expenses after claiming she lived in Kent when her actual home was in east London.
The wealthy businessman Lord Paul repaid £38 000 after admitting he had never spent a night at the one-bedroom Oxfordshire cottage he listed as his main home.
He was suspended from the Lords for four months after the privileges committee concluded he had not acted dishonestly or in bad faith.
Although never seen in the upper house, the millionaire novelist Lord Archer is still formally a member. He was jailed for four years in 2001 after being found guilty of perjury and perverting justice by lying on oath in a libel case 14 years earlier.
The Independent