He made the comments as he visited West Yorkshire Police's headquarters at Carr Gate, Wakefield, following the launch of a national campaign to recruit 20,000 extra police officers.
A cross-party bid to require the PM to ask for a Brexit extension if there is not a deal in place cleared the Commons on Wednesday and is due to complete its progress through the Lords on Friday.
Asked if he could make a promise to the public not to return to Brussels to ask for a further Brexit delay, the PM said: "Yes, I can.
"I would rather be dead in a ditch."
But he declined to give a direct answer when asked if he would resign before requesting that delay.
Instead, he said: "It costs a billion pounds a month, it achieves absolutely nothing. What on Earth is the point of further delay? I think it's totally, totally pointless."
The Prime Minister said he hated "banging on about Brexit" and added: "I don't want an election at all, but frankly I cannot see any other way.
"The only way to get this thing done, to get this thing moving, is to make that decision.
"I think it's a no-brainer and I'm sorry to bring this painful subject up this afternoon but that's the reality of what we face and for me there can only be one way forward for our country."
Mr Johnson acknowledged a Brexit split with his brother Jo who quit the Government earlier today saying he had been "torn between family loyalty and the national interest".
Jo Johnson, who had been a senior minister attending meetings of his brother's Cabinet, said it was an "unresolvable tension".
The Prime Minister said his brother "does not agree with me about the European Union because it's an issue that obviously divides families and divides everybody".
A West Yorkshire Police trainee appeared to faint during the Prime Minister's speech after he kept officers waiting for more than an hour.
In the final moments of his speech, the trainee standing directly behind the PM put her hand to her head and sat down on the floor, apparently unable to stand any longer.
His speech was met with anger by a number of Yorkshire MPs.
Wakefield Labour MP Mary Creagh tweeted: "Keeps them waiting in the sun for an hour. Carries on spouting when a recruit feels faint & sits down. We saw today how Johnson treats the police."
Yvette Cooper MP also tweeted: "This is an abuse of power by Boris Johnson, making so many police stop their training and work to be part of his political stunt. They have a job to do here in West Yorks, and they train and work hard for the whole community - completely unacceptable to use them in this way"