Police have reopened an investigation into potential Covid breaches at a pandemic-era party in Tory headquarters – and launched a fresh probe into a second alleged gathering of Tory MPs in Parliament during the same month.

The Metropolitan Police said new evidence that was “not previously provided” had prompted officers to look again at the December 14 2020 Christmas event at Conservative Campaign Headquarters.

The force has also launched a new probe into an event in Parliament on December 8 of the same year, when Privileges Committee member Sir Bernard Jenkin is reported to have attended a “birthday drinks” event for his wife in Parliament.

However, the Met – along with Thames Valley Police – will not be investigating potential further breaches involving Boris Johnson and others at Downing Street and at Chequers between June 2020 and May 2021.

The December 8 gathering was cited by Boris Johnson in a scathing statement accusing Sir Bernard of “monstrous hypocrisy” for allegedly attending the event before sitting on the cross-party panel which found the former prime minister had lied to MPs with his partygate denials.

The drinks are said to have been arranged by Commons Deputy Speaker Dame Eleanor Laing while London was in Tier 2 measures that restricted indoor socialising.

A spokeswoman for the Speaker’s Office said: “As this is a live investigation any further inquiries should be directed to the Met Police.”

The PA news agency understands Dame Eleanor will not be stepping down as Deputy Speaker while the investigation continues.

Sir Bernard said: “It is not appropriate to comment on a continuing investigation.”

The Met had previously investigated the CCHQ “jingle and mingle” event in December 2020 but decided there was “insufficient evidence” to take further action.

Both former London mayoral candidate Shaun Bailey and Tory aide Ben Mallett – who were handed a peerage and an OBE respectively in Mr Johnson’s resignation honours – attended the gathering.

In a clip published by the Mirror last month, Conservative Party staff appear to dance, drink and joke about Covid restrictions.

Mr Bailey, who remains a London Assembly Member, resigned as chairman of the governing body’s Police and Crime Committee after the picture emerged.

The Met issued 126 fines over rule breaches in Whitehall and Downing Street while Mr Johnson was prime minister, in a scandal that helped end his tenure in No 10.

Mr Johnson and his then-chancellor Rishi Sunak paid fixed-penalty notices over a gathering held for Mr Johnson’s 56th birthday.

The Met said in a statement: “The Met and Thames Valley Police have assessed new material in relation to potential breaches of Covid Regulations in 2020 and 2021. The Met will be opening one investigation and re-opening a previous investigation.

“The approach to the assessment of these events has been consistent, enforcing the law carefully, thoroughly, proportionately, impartially and without fear or favour.

“The Met has previously published criteria for assessing when to launch investigations into breaches of the Regulations reported retrospectively.”

The force added it would only do so when there was evidence of a “serious and flagrant” breach of the rules and said it would provide further updates at an “appropriate time”.

Addressing the material it had been referred to over Mr Johnson’s time in Chequers and Downing Street, the Met said it had assessed the events alongside Thames Valley and found they did “not meet the retrospective criteria” for opening an investigation.

The Liberal Democrats renewed calls for Shaun Bailey’s peerage to be paused as police investigate the Tory headquarters gathering during Covid restrictions.

Deputy leader Daisy Cooper said: “Rishi Sunak needs to confirm he will call for honours to be stripped from anyone found to have broken the law. Anything less would make a complete mockery of his pledge to lead with integrity.

“He should also step in to stop Shaun Bailey from taking his seat as a peer while this investigation takes place.”