Scotland Yard is to "assess" whether any criminal offences were committed by Keith Vaz MP, after allegations of drug use and hiring escorts were made in a Sunday newspaper report last weekend.
The Metropolitan Police confirmed this afternoon it had received a letter on Wednesday requesting that police consider the allegations made by the Sunday Mirror on 4 September.
The Met said the letter has been forwarded to the Met's special inquiry team, part of its specialist crime and operations, to "assess and identify what criminal offences - if any - may have been committed".
At this stage a police investigation has not been launched, the Met said.
Earlier this week, Labour MP Vaz resigned as chair of the home affairs select committee over the allegations.
He had been at the head of the committee since 2007.
"It is in the best interest of the home affairs Select committee that its important work can be conducted without any distractions whatsoever," Vaz said in a statement on Tuesday.
"I am genuinely sorry that recent events make it impossible for this to happen if I remain chair. I have always been passionate about select committees, having served as either chair or member for half of my time in parliament.
"The integrity of the select committee system matters to me. Those who hold others to account, must themselves be accountable."
Earlier this week it emerged Labour MP Chuka Umunna had become the first to bid to replace Vaz on the home affairs select committee.