A Number 10 spokesman said Boris Johnson will today "speak directly to the public, setting out the vital choice that faces our country".
"He will argue that Jeremy Corbyn's Surrender Bill will force the Prime Minister to go to Brussels and surrender to any demands they make. This would, in essence, overturn the biggest democratic vote in our history - the 2016 referendum.
"The PM will not do this.
"It is clear the only action is to go back to the people and give them the opportunity to decide what they want: Boris to go to Brussels and get a deal, or leave without one on October 31 or Jeremy Corbyn arriving in Brussels with his surrender bill begging for more delay, more dither and accepting whatever terms Brussels imposes over our nation."
The spokesman added: "For Jeremy Corbyn to continue to avoid an election would be a cowardly insult to democracy."
Chancellor Sajid Javid Chancellor said: "What we have now is a situation where the Leader of the Opposition is trying to get his way which is to basically make sure that we never leave the European Union, he is trying to do that by kiboshing the negotiations the Government is carrying out on behalf of the British people."
He told the BBC he was "sad to see 21 colleagues, 21 Conservatives no longer carrying the Conservative whip, of course I am, these are my friends, these are good people".
"But they also knew that when the Prime Minister of the day says a vote is a matter of confidence what would be the consequences of opposing that.
"This is not something I want to see but we do need to step back and think about how do we deliver on the central mission to leave the EU by October 31 and continue to govern this country in a way that the people are feeling that their priorities are being met."
Shadow chancellor John McDonnell acknowledged splits in Labour about the timing of a general election.
He said the Labour leadership was in contact with legal experts, other opposition parties and the Parliamentary Labour Party about what to do and "people have got different views on this".
"The problem that we have got is that we cannot at the moment have any confidence in Boris Johnson abiding by any commitment or deal that we could construct," he told BBC Radio 4's Today.
"That's the truth of it. So, we are now consulting about whether it's better to go long, therefore, rather than to go short."
In response to Downing Street's attack on "cowardly" Jeremy Corbyn, Mr McDonnell said: "I wish he would put aside Donald Trump's script for a time and have a serious discussion.
"What's happening now he's demeaning the office of Prime Minister, he really is.
"We want a general election as well but we want it in the interests of the country when we have prevented a no-deal Brexit, and on that basis we have got to determine the date."
Tory former Cabinet minister Damian Green is the leader of the One Nation group of Conservatives who have called for reinstatement of the 21 rebels kicked out of the party.
He told the BBC: "I'm afraid it does look as though somebody has decided that the moderate, progressive wing of the Conservative Party is not wanted on voyage.
"That's wrong in principle because there are many Conservative traditions, but it is terrible practical politics to narrow your appeal just before a general election."