Symonds did not appear by Johnson's side at the Birmingham hustings today. On Saturday the Guardian reported that police were called to the home Johnson and Symonds share after a neighbour heard screaming during an apparent row between the couple.
The newspaper disclosed that Symonds could be heard on a tape telling Johnson to "get off me" and "get out of my flat". At one point Johnson could be heard saying "get off my f***ing laptop" before a loud crashing noise. Symonds told Johnson he had ruined a sofa with red wine.
Penn said he leaked his recording to the Guardian because Johnson should be "held accountable" for all of his "words, actions, and behaviours".
Leigh, a pro-EU theatre producer and writer, recently wrote on social media about an incident in which she made a rude gesture to Johnson outside the building in south London.
The 34-year-old American also claimed on Twitter last week that Conservative politicians were "pretending to respect the memories of the Holocaust dead" and previously stated that British Prime Minister Theresa May was responsible for "insanely cruel policies" affecting immigrants and the poor.
She recently posted on the site: "Just gave Boris Johnson the finger, this weekend is unstoppable." Both hers and Penn's Twitter profiles had been deactivated by yesterday morning.
Yesterday, James Cleverly, the former Conservative chairman, appeared to suggest that the MP's neighbours had called the police in order to cause trouble for Johnson, who is competing with Jeremy Hunt to succeed May as Tory leader.
Today, a ComRes poll of Tory councillors for the Sunday Telegraph put Johnson ahead his rival by 61 per cent to 39.
A Survation poll showed that among the general public, Hunt was ahead of Johnson by 52 per cent to 48. But among Conservative voters, who choose the leader, Johnson had 57 to 43 per cent.
"The big element in the Boris story isn't that there was a heated argument, it's that the police were called," Cleverly said.
"The police were called by the same person who recorded Boris and gave the story to the Guardian."
In the hours before the argument flared up, the Telegraph understands that Symons had been upset by reports that John Worboys, the black-cab rapist, had admitted further sex assaults.
In her late teens, Worboys had picked her up and had drugged her.
Revealing his identity in a statement published on the Guardian website last night, Penn said: "In the early hours of Friday morning, I answered a phone call from a takeaway food delivery driver. At the same time, I heard what sounded like shouting coming from the street. I went downstairs, on the phone to the driver and collected my food. On the way back into my flat, it became clear that the shouting was coming from a neighbour's flat. It was loud enough and angry enough that I felt frightened and concerned for the welfare of those involved, so I went inside my own home, closed the door, and pressed record on the voice memos app on my phone.
"After a loud scream and banging, followed by silence I ran upstairs and with my wife agreed we should check on our neighbours. I knocked three times at their front door but there was no response. I went back upstairs into my flat, and we agreed that we should call the police.
"The police arrived within five minutes... They subsequently called back to thank us for reporting and to let us know that nobody was harmed. To be clear, the recordings were of the noise within my own home. My sole concern up until this point was the welfare and safety of our neighbours. I hope that anybody would have done the same thing. Once clear that no one was harmed, I contacted the Guardian, as I felt it was of important public interest.
"I believe it is reasonable for someone who is likely to become our next prime minister to be held accountable for all of their words, actions, and behaviours. I, along with a lot of my neighbours all across London, voted to remain within the EU. That is the extent of my involvement in politics."
Scotland Yard said in a statement that they responded to the call but "there was no cause for police action."
