Traces of cocaine were also reportedly identified in lavatories nearest the private offices of Boris Johnson and Priti Patel, the Home Secretary, as well as a disabled bathroom near to Labour’s shadow cabinet offices.

The tests were all carried out on the same evening using cocaine detection wipes, which are more often used in nightclubs and bars to identify and minimise onsite drugs consumption.

Several sources also alleged casual cocaine use by a group of MPs, with one stating they had seen an MP “openly snorting cocaine at a party”, while another said they had been told of a member of staff walking in “on their MP doing a late-night line at their desk.”

Responding to the findings, Sir Charles Walker MP, the Tory chairman of the House’s administration committee, said that the issue would be discussed by the commission responsible for the administration and services of the Commons.

Ahead of the meeting, he told the paper: “The House of Commons has a long history of using sniffer dogs to detect explosives. It may be that we now need to broaden the range of sniffer dogs . . . to include those which can detect drugs.”