The audience jeered LBC presenter Iain Dale over the question and the Tory leadership candidate said it was obvious the audience was not interested.
The Tory faithful then cheered Boris.
And key supporter Jacob Rees-Mogg tweeted: “An excellent performance from Boris Johnson at the first hustings.
“Strong, clear answers and we will leave by October 31.”
The grilling came before neighbour Tom Penn went public on the phone call.
Police subsequently visited the house and no charges were made.
However, Mr Penn then took a recording of the arguement between mr Johnson and Ms Symonds to the Guardian newspaper, who published parts of then row.
In a statement defending his actions, Mr Penn wrote: “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.”
He added: “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.”
On contacting the newspaper he said: “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.”