Twenty fines are set to be issued over alleged lockdown-busting parties held in government buildings, police have said.

The Metropolitan Police said on Tuesday that investigators will begin to refer the notices to the ACRO Criminal Records Office, which would be responsible for issuing the fines.

It is expected that further fines could be issued as officers continue to go through the evidence gathered.

The force said: “The investigation into allegations of breaches of Covid-19 regulations in Whitehall and Downing Street has now progressed to the point where the first referrals for fixed penalty notices (FPN) will be made to ACRO Criminal Records Office.

“We will today initially begin to refer 20 fixed penalty notices to be issued for breaches of Covid-19 regulations. The ACRO Criminal Records Office will then be responsible for issuing the FPNs to the individual following the referrals from the MPS.

“We are making every effort to progress this investigation at speed and have completed a number of assessments. However, due to the significant amount of investigative material that remains to be assessed, further referrals may be made to ACRO if the evidential threshold is made.”

The Met would not confirm how many individuals will receive fines, or their identities.

It said: “As it has for all fixed penalty notices issued during the pandemic, the MPS will follow the College of Policing Approved Professional Practice for Media Relations which states that “Identities of people dealt with by cautions, speeding fines and other fixed penalties – out-of-court disposals – should not be released or confirmed.”

“We will not confirm the number of referrals from each individual event subject to our investigation as providing a breakdown at this point may lead to identification of the individuals.”

However, Downing Street will confirm if the Prime Minister is issued with an FPN, but it is not expected to confirm the identities of more junior members of staff who are hit with fines.