"There’s obviously several thousands of people who work on this estate and I’d be surprised if there weren’t some lifestyle users of drugs among them, I have to say", Malthouse told Sky News broadcaster when asked about The Sunday Times report that out of 12 parliamentary sites tested for cocaine, 11 came back positive.
Reacting to the newspaper's report, House of Commons Speaker Lindsay Hoyle announced on Sunday that he will call in the police to investigate the allegations.
"The accounts of drug misuse in Parliament given to the Sunday Times are deeply concerning, and I will be raising them as a priority with the Metropolitan Police next week. I expect to see full and effective enforcement of the law", Hoyle said in a statement.
Labour lawmaker and shadow Home Minister Yvette Cooper backed the speaker's decision to refer the reports to the police.
"You can't have an institution that's supposed to be law-making and in fact have within it so much law-breaking, so I think it's absolutely right that this is properly investigated", she told Sky News.
The media report on the alleged drug use in parliament came a day before the UK government was due to unveil a £700 million ($928 million) plan to tackle the problem by providing rehabilitation programs for drug users and targeting drug dealers.