Boris Johnson faces a showdown in Parliament later after No 10 officials warned he would call for a snap general election on 14 October if MPs succeed in seizing control of Commons business.
Rebel Tories and Labour MPs are planning a bill to stop the UK leaving the EU on 31 October without a deal.
Mr Johnson said he did not want an election, but progress with the EU would be “impossible” if the MPs win.
Former chancellor Philip Hammond said he would vote for the bill.
He told BBC Radio 4’s Today that he believed “there will be enough people for us to get this over the line today” and called it “rank hypocrisy” for Downing Street to have threatened rebel MPs with expulsion from the party and deselection.
Jeremy Corbyn said the Labour Party was ready for a general election.
But shadow Northern Ireland secretary Tony Lloyd later said Labour would vote against any government plans to hold a general election before the UK is due to leave the EU on 31 October.
He said Labour “will not have Boris Johnson dictate the terms of an election that crashes this country out with no deal”.
Under the Fixed-term Parliaments Act, Mr Johnson would require the backing of two-thirds of the UK’s 650 MPs to trigger a poll in the autumn.
A number of MPs have come together across party political lines in a fresh bid to stop a no-deal Brexit, after Mr Johnson vowed to leave the EU with or without a deal on 31 October.
When Parliament returns on Tuesday after recess, they are expected to put forward legislation under Standing Order 24 – a rule that allows urgent debates to be heard.
