Hundreds of angry constituents have been contacting Tory MPs about reports of parties being held in Downing Street while Covid restrictions were in place.
Some MPs say their inboxes have filled up after No 10 apologised to the Queen for two staff parties the night before the Duke of Edinburgh’s funeral.
The government has urged people to reserve judgement for an inquiry.
Boris Johnson was not at either party last April before Prince Philip’s funeral – but he faces questions over alleged Covid rule-breaking at No 10.
One senior backbench Conservative MP told the BBC they received more than 200 angry emails about the parties, with only five messages in support of the prime minister.
The gatherings which Downing Street has apologised to Buckingham Palace for took place on 16 April 2021.
The two parties last April involved around 30 people in total, and are reported to have converged at some point in the Downing Street garden, where they continued past midnight.
Staff were reportedly sent to a nearby shop with a suitcase, which was brought back “filled with bottles of wine”.
At the time, England was under “step two” restrictions that stipulated people could not socialise indoors, except with those from their household or support bubble. People could socialise outdoors in groups of up to six people or two households.
The behaviour of No 10 staff has been contrasted with pictures of the Queen sitting alone at the Duke of Edinburgh’s funeral, due to Covid restrictions.
Boris Johnson’s spokesman said it was “deeply regrettable that this took place at a time of national mourning”.