Boris Johnson’s speech outside No.10 on Monday evening was timed for maximum impact – commanding the beginning of the six o’clock news, and coming at the end of another day dominated by plots to block a no-deal Brexit.

But as he opened his mouth to speak, so did a group of loud protesters, who nearly succeeded in completely drowning out the prime minister’s voice.

At some points the chanting was almost equal in volume to the PM’s speech in footage broadcast on Monday evening.

“Stop the coup” has become the chant of choice among protestors angered by the PM’s decision to suspend parliament.

Johnson has been urging Tory MPs not to support measures to block a no-deal Brexit, amid speculation he could call an election if he loses the Commons showdown.

The prime minister insisted “I don’t want an election, you don’t want an election” but he said he would not seek an extension to the Brexit deadline – which is what the cross-party alliance are demanding if there is not a deal.

But shortly after the speech, a senior government source said Johnson will attempt to force a snap general election on October 14 if MPs vote to block a no-deal Brexit on Tuesday.

The prime minister has insisted there are “no circumstances” in which he would ask the EU to delay Brexit beyond October 31.

If MPs on Tuesday vote to seize control of the Commons to pass laws, which could oblige Johnson to seek a Brexit delay to January 31 2020, he would look to call a general election, the source said.

Speaking on the steps of No.10 Downing Street on Monday evening, Johnson said if MPs voted against the government they would “chop the legs” out from under the UK’s negotiating position with Brussels.