A week is a long time in politics, said UK Prime Minister Harold Wilson during one of the greatest periods of social and industrial change in the 20th century.

However, if Wilson were alive today, he might have said a day was a long time in British politics, with the Brexit crisis on the country’s leaving the European Union redefining the role of political traditions in a country without a written constitution.

In the last 24 hours, Britain was firmly put on an early election footing after Downing Street confirmed that Prime Minister Boris Johnson would call an early election if his opponents in parliament managed to pass legislation blocking his plans for a departure from the EU by the 31 October deadline.

If the early election announcement was meant to discourage Johnson’s opponents in parliament from challenging him, it did the opposite, however.

Former finance minister and Conservative Party rebel Philip Hammond said he thought there was enough support for a bill seeking to delay the UK›s exit date to get through parliament.

Hammond told the BBC that he believed “there will be enough people for us to get this over the line.” He also refuted Johnson’s claim that there had been progress in the talks with the EU, arguing that the government was making “no progress” on getting a new Brexit deal.

He called it “rank hypocrisy” for Downing Street to have threatened Conservative rebel MPs with expulsion from the party and deselection.

He was reselected by his local Conservative Party association on Monday to stand as its candidate in the next election, and he added that he did not believe Number 10 had the power to deselect him.

 Johnson has taken steps to suspend parliament during part of the period before the Brexit deadline, giving legislators little time to try to rush through legislation designed to prevent a disorderly departure. The MPs are facing daunting challenges to pass a law before the possible suspension of parliament on 9 September.

There is thus another showdown between the UK government and parliament over a crucial decision about whether MPs should intervene to prevent a possible “no-deal” exit from the European Union.

The possible legislation, supported by the opposition parties and around 20 Conservative MPs, seeks to tie Johnson’s hands and instructs him to ask the EU for an extension of the Brexit process until 31 January 2020.

The most significant clause is one which says that if the European Council proposes an extension to a different date, the prime minister must accept it within two days unless that extension has been rejected by the House of Commons.

The clause means that the extension decision will be in the hands of parliament not the government.

However, a bill introduced in the House of Commons, the lower chamber of the UK parliament, gets two “readings,” one with a debate, before it goes to a committee stage, during which every clause is discussed and amendments can be made.

It then goes back to the House of Commons for more debate and possibly more amendments and then is voted on at the end of a “third reading.”

If the bill is passed, it goes to the upper chamber, the House of Lords, for a similar series of steps. If the Lords have made amendments to the bill, it is then sent back to the Commons for further consideration. If the Lords do not make changes, the bill is sent to Queen Elizabeth II for royal assent and becomes law.

The queen’s approval is seen as a formality and does not have to be given in person.

But time is short for MPs to block any no-deal Brexit, with fewer than 60 days before the withdrawal date and a lengthy parliamentary suspension in the offing.

In a desperate attempt to stop Conservative MPs from supporting the legislation, Johnson described the parliamentary action to stop a no-deal Brexit as “chopping the legs” off the UK’s position. He spoke moments after lawmakers had posted a copy of the proposed bill on Twitter, making clear that they would press the government to seek a delay if there was no deal.

Johnson has insisted that the potential for a no-deal Brexit must remain an option in the negotiations with the EU. The bloc is adamant it will not renegotiate the agreement struck with former UK prime minister Theresa May on the terms of Britain’s departure and the framework of future relations.

“Let’s let our negotiators get on with their work, without that Sword of Damocles over their necks, and without an election,” he said. “I don’t want an election; you don’t want an election. Let’s get on with the people’s agenda.”

Despite Johnson’s comments, Downing Street said later that he would call an early election if his opponents in parliament managed to pass legislation that would block his plans for Brexit by the deadline. His goal would be to gain a majority in a new parliament that would back his Brexit stance.

Johnson, who took power in July with a pledge to leave the EU by 31 October no matter what, insisted that he was not backing down on his promise.

“There are no circumstances under which I will ask Brussels to delay,” Johnson said. “We’re leaving the 31st of October, no ifs or buts.”

Johnson’s option to call a general election would be supported by opposition Labour Party leader Jeremy Corbyn, who vowed to “take the fight to the Tories” in a general election and insisted that the Labour Party was ready.

 “I will be delighted when the election comes. I’m ready for it, you’re ready for it, we’re ready for it,” he said.

But shadow cabinet colleague Tony Lloyd told the BBC that Labour would not “fall for Boris Johnson’s trick” by agreeing to a general election before 31 October. “We are not daft enough to see a tactic dictated by Johnson which is designed to land us with a no-deal Brexit and to fall for that,” he said.

He said the focus was on “building an all-party consensus to stop a no-deal Brexit.”

Labour backbencher Mary Creagh said her understanding was that the party would not support a vote for a general election to take place before 31 October. Lib Dem MP Layla Moran said she would not support triggering a general election while no-deal remains on the table.

Under the UK’s fixed-term parliaments act, Johnson would require the backing of two-thirds of the UK’s 650 MPs to trigger a poll in the autumn.

Downing Street denied it would try to change the election date, but no one trusts Johnson and his team, who firmly denied the intention to suspend parliament during September and October before threatening to do exactly that. 

Johnson stopped short of formally committing the government to abide by parliament’s wishes if legislation is passed. Cabinet Minister Michael Gove, who is playing a role in the Brexit preparations, also said the government would wait and see what, if any, legislation was passed before deciding on its response.

Their position puts Britain on the path of constitutional crisis, as no prime minister has previously said he would not respect a law passed by parliament.