Johnson then talked over the protester saying he would be getting back to parliament "very soon".
Speaking in Yorkshire, Mr Johnson said that the "rough shape" of an agreement was emerging, adding that his team was "working incredibly hard to get a deal" and had made a "good deal of progress".
Despite Mr Johnson's upbeat assessment, Downing Street sources played down the prospect of a breakthrough, cautioning there was still "a long way to go".
But there have been fears Mr Johnson may try to wriggle out of the request, after he said he would rather be "dead in a ditch" than ask for a delay to the Halloween deadline.
Mr Maugham said that they have selected Scotland for the case because judges there have the "nobile officium" power that could allow the court to sign the letter if the PM refuses.
"Whatever the shenanigans that may be going on at Westminster, we will get on with delivering our agenda and preparing to take this country out of the European Union on October 31", he said.
On Friday, Lord Menzies and his colleagues Lord Brodie and Lord Drummond Young ruled that the Prime Minister has seven days to lodge his response to the petition brought by the remainer campaigners.
He ruled that whether or not to prorogue Parliament was for politicians, not the courts, to decide.
The Prime Minister did not react as one man was heard telling him: "Find a deal here - this is Doncaster, not Europe".
"UK must leave as one nation". Such action is unlawful and wrongful.
He continued: "Why are you not in Parliament sorting out the mess that you have created?"
Lord Menzies said: "We will grant your motion".