Metropolitan Police Commissioner Cressida Dick is set to be quizzed on Downing Street parties this week, the Mirror has learned.
Despite growing evidence of parties held at Number 10 during lockdown, the Met Police has said it had no plans to investigate any of the alleged parties.
Most recently the force has said it will certainly not launch an inquiry while Whitehall enforcer Sue Gray is conducting an internal inquiry.
But on Tuesday, members of the London Assembly Committee Shaun Bailey once chaired, will quiz the Met Police chief.
Mr Bailey quit his post as chair of the Police and Crime Committee (PCC) following revelations of his "raucous" lockdown breaching party before Christmas.
Now, the PCC will make the most of Cressida Dick's appearance on Tuesday quizzing her on the parties that have been held in line with evidence.
The Mirror understands London Assembly member's Caroline Russell of the Green Party and assembly member Caroline Pidgeon of the Liberal Democrats will lead the questions.
Lib Dem leader Ed Davey previously said the police "mustn't turn a blind eye" on the parties.
"Cressida Dick mustn't let him off the hook through a shady establishment stitch-up. The police don't need the government's permission to investigate a crime, and they mustn't turn a blind eye to criminality just because it is committed by Boris Johnson," Mr Davey said.
"It is ludicrous to pretend that we can leave it to a civil servant appointed by Boris Johnson to get to the bottom of this."
It comes as Ms Gray is understood to have had an "ongoing dialogue" with Scotland Yard about her investigations into Downing Street parties, the Sunday Times reports.
The top civil servant is expected to publish her highly-anticipated report later this week.
Ms Gray's report will include at least 13 events from the official Downing Street Christmas Party held on December 18 and the party held the night before Prince Philip's funeral.
She is expected establish a “general understanding of the nature of” the gatherings in question, rather than full details of what went on in regards to each incident.
Fresh reports claim Ms Gray has widened her inquiry to include Carrie Johnson who reportedly allowed two of her close friends to visit the the flat she shares with the Prime Minister during lockdown.
Senior Cabinet Office official Sue Gray has received evidence that Josh Grimstone and Henry Newman went to Carrie's flat several times while Covid restrictions were in place.
Andrew Selous and Stephen Crabb are among Tory MPs who have called the Met police to launch a probe into the parties.