Earlier today, the prime minister admitted in parliament that he attended a drinks party in Downing Street during the first Covid-19 lockdown.
Eyewitnesses say he and his wife Carrie were among roughly 30 people who attended the 'bring your own booze' (BYOB) party in May 2020 - a time when lockdown restrictions meant people were forbidden to meet more than one other person outdoors.
Labour MP for Portsmouth South, Stephen Morgan, said: 'It is utterly ridiculous that the prime minister seems to suggest he had no idea he was at a party. It's a slap in the face for people in Portsmouth and across the country that diligently followed the rules.
'People suffered unimaginable loneliness, hurt and grief during the pandemic. The prime minister’s partying is beyond offensive to all of them. But to now try and hide behind an investigation, spokespeople or civil servants is frankly shameless.
'It is time for him to finally take responsibility for what he has done. The party is over. Boris Johnson must resign.'
Fellow Labour MP for Southampton Test, Dr Alan Whitehead, added: 'I do think at this point the prime minister should resign. This behaviour from him and his inner circle is no longer shocking coming at the end of a long line of rule bending and breaking over the last year or so.
‘It is incredibly frustrating and upsetting that while the majority of local people were doing the right thing trying to keep their loved ones and wider community safe, Boris Johnson was allegedly having garden parties.
‘Many Southampton people were contacting me at that time, weddings having been cancelled, businesses at risk of closure, mental health suffering. They made untold sacrifices that apparently Boris Johnson and his team were not willing to make. We cannot have one rule for the government and another for everyone else.’
Conservative MPs have also voiced their frustration at the prime minister's flouting of the very rules he set.
Meon Valley MP Flick Drummond said: 'I am very disappointed to hear the prime minister admit he went to an event with drinks in the garden at Downing Street during the first lockdown.
‘I share the concerns of the public about this when so many kept to the rules and made sacrifices to do so.
‘I will now wait to see the findings of the investigation into what happened before I comment further.’
Portsmouth North MP Penny Mordaunt said: 'Like many others, including my constituents, I am extremely disappointed at these events.
‘The stupidity of what took place, the stark contrast to the discipline and sacrifices others were making and also the bandwidth the current situation is now taking up, while we are facing massive challenges at home and abroad.
‘I'm glad the PM gave some answers today and apologised. I briefly spoke to him today too and know he understands how people feel.'
Romsey and Southampton North MP, Caroline Nokes, added: 'I wasn’t invited to the event – I am, like the vast majority of my constituents, angry about this.
'I have made my views clear to the chief whip and my correspondence to constituents has been widely published.'
Fellow Conservative MPs Caroline Dinenage, Suella Braverman, Alan Mak, Damian Hinds and Sir Desmond Swayne were also contacted by the Local Democracy Reporting Service, but did not comment.