Rishi Sunak has received a questionnaire from police investigating the partygate affair.
The Chancellor has joined the prime minister, and other Downing Street staff, in being questioned by the Metropolitan Police..
It is understood Sunak attended a birthday party for Boris Johnson in the Cabinet Room in June, 2020 - one of the alleged gatherings under investigation.
A source close to the Chancellor confirmed to HuffPst UK that he has received a questionnaire asking him to explain his attendance at the event.
He has a week to fill in the form and return it to the Met.
If he is found to have broken the anti-Covid social distancing rules that were in place at the time, he faces receiving a fixed penalty notice.
A copy of one of the questionnaires was leaked to ITV earlier this week, revealing that recipients were effectively being interviewed under caution.
Recipients were told that they “do not have to say anything but it may harm your defence if you do not mention we questioned something which you later rely on in court”.
Respondents are advised to “ensure the caution is read and understand prior to any answers to questions being provided”.
The document goes on to say that those sent the questionnaire are being provided with the “opportunity to cooperate with police in the form of a written statement under caution”.
Among the questions posed are “What, if any, lawful exception applied to the gathering and/or what reasonable excuse did you have for participating in the gathering?”
It meant that Boris Johnson is the first prime minister ever to be interviewed under caution.
When Tony Blair was prime minister during the cash for honours scandal, he was interviewed by police as a witness.
He let it be known to aides that if he were interviewed under caution, he would have to resign.