DISGRACED peer Lord Sewel will not face charges over allegations of drug-related offences after Scotland Yard said there was "insufficient evidence to proceed" with its investigation.

In July, the 69-year-old scandal-hit parliamentarian resigned from the House of Lords after coming under intense pressure over footage of him allegedly taking cocaine with two prostitutes apparently at his flat in London. 

The former Scotland Office Minister, best known for giving his name to the Sewel Motion, apologised for the "pain and embarrassment" caused by the drugs and sex scandal, exposed in the Sun on Sunday. 

The Scottish politician, who lives near Aberdeen, was the first peer to stand down in disgrace following new rules introduced last year allowing resignations from the Upper House.

The Metropolitan Police said in a statement: "The Met launched a criminal inquiry into allegations of drug-related offences involving a member of the House of Lords on Monday July 27

"The investigation, led by officers from the Special Enquiry Team of the Homicide and Major Crime Command, has now concluded.

"Following a review of all the material, including a forensic examination of an address in central London, there is insufficient evidence to proceed with this investigation and the matter is now closed."

The married father-of-four resigned from his £84,500-a-year role as Deputy Speaker of the Lords and Chairman of the Lords Privileges and Conduct Committee; the body, which oversees issues of conduct and probity and which was set to investigate claims of misconduct before Lord Sewel quit the UK Parliament altogether. He was also suspended by the Labour Party.

Video footage showed the peer snorting white powder - alleged to be cocaine - from a prostitute's breasts using a £5 note. He was also pictured wearing an orange bra and leather jacket as he reclined smoking a cigarette.

In a conversation supposedly recorded in Lord Sewel's flat a couple of miles from the UK Parliament, the ex-Scotland Office Minister branded David Cameron "the most facile, superficial Prime Minister there's ever been".

He labelled Boris Johnson, the London Mayor, "a joke" and a "public school upper class twit", and described Alex Salmond, the former First Minister, as a "silly, pompous prat".

In a statement to parliamentary officials announcing his resignation, the peer said: "I hope my decision will limit and help repair the damage I have done to an institution I hold dear...I want to apologise for the pain and embarrassment I have caused."

At the time, the Prime Minister welcomed his decision to "absent himself" but played down the prospect of further reform of the Second Chamber, saying there was "no point in trying that route again" after the failure of proposals under the Coalition.

But Baroness Boothroyd, the former Commons Speaker, described Lord Sewel as a "bad apple", who had "brought the House into some disrepute".

The scandal fuelled criticisms that the unelected House of Lords was out of touch and should be scrapped.

The chamber has swollen in size in recent years, and there are currently 783 members, making it the largest legislative assembly outside the People’s Republic of China.