[14] She was succeeded after the following leadership election as leader and prime minister by Boris Johnson, who pledged, "do or die", to withdraw the UK from the EU on 31 October, with or without a deal.

The rebels included the Father of the House and former Chancellor of the Exchequer, Ken Clarke, eight other Cabinet ministers under Cameron and May, and Winston Churchill's grandson, Nicholas Soames.

The Government made clear its opposition to the bill from the beginning, and said that, were it to pass through the House of Commons, the prime minister, Boris Johnson, would immediately bring forward a motion under the Fixed-term Parliaments Act for a general election.

[31][32] In response to the bill's passage on 4 September, the Government immediately brought a motion for an early general election under the terms of the Fixed-term Parliaments Act 2011.

[34] On 5 September, at a press conference at a police training school in Wakefield, West Yorkshire, Johnson said he would rather be "dead in a ditch" than request an extension to Article 50.

[37] By 9 September, reports surfaced that the Government would seek to bypass the law by sending a request for an extension as required by the Act alongside another letter that declared the request invalid; former Supreme Court justice Lord Sumption described such an act, in the face of judicial action, as a possible contempt of court that would risk the resignations of the law officers in his Cabinet,[38] while former Director of Public Prosecutions Ken Macdonald said Johnson was risking imprisonment for the same offence.

[41] On the same day, Liz Saville Roberts, the leader of Plaid Cymru in the House of Commons, announced she had entered discussions with other parties to gather support for impeachment if Johnson refused to obey the law.

[43] Plaid Cymru had spearheaded the last serious impeachment attempt, an unsuccessful 2004 effort to indict then-Prime Minister Tony Blair for lying to Parliament regarding the Iraq War.

[42] Johnson, then a member of the opposition frontbench, was another high-profile supporter of the effort to impeach Blair and wrote a column in The Daily Telegraph that accused him of "treating Parliament and the public with contempt".

[44] On 26 September 2019, former Prime Minister John Major said in a speech to the Centre for European Reform that he "feared" that Johnson would use an Order of Council to nullify the Act until after 31 October.

[46] The following afternoon, 10 Downing Street denied Johnson would use Orders of Council to bypass the Act, but reiterated the Government's commitment to leaving the EU on 31 October.

Cherry, the justice spokeswoman for the Scottish National Party, and Maugham had successfully brought a case before the Court of Session to challenge Johnson's prorogation of Parliament, which had delivered a judgment that declared it unlawful on the previous day.

[48] On 24 September 2019, the Supreme Court ruled in R (Miller) v The Prime Minister and Cherry v Advocate General for Scotland that the prorogation was unlawful and void; as a response, Parliament was recalled to sit the following day.

On 9 October, the Inner House of the Court of Session decided that a final ruling on the petition would not be made until 21 October—two days after the deadline in the Act for the Prime Minister to request an extension.

[52][53] Following a special sitting of Parliament on Saturday 19 October, the Benn Act required the prime minister immediately to write to the European Council with a request for an extension of withdrawal until 31 January 2020.

[59] The Prime Minister's description of the law as a "Surrender Act" in Parliament was criticised by Dewsbury MP Paula Sherriff, who said his language was unnecessarily inflammatory and said that opposition politicians routinely received death threats that similarly called the law a "Surrender Act" and accused MPs of "betrayal" and that Johnson should moderate his language; Johnson received heckles of "shame" when he described Sherriff's comments as "humbug".

[60] Tracy Brabin, the then MP for the neighbouring constituency of Batley and Spen, also asked Johnson for moderation to prevent violence against MPs; her predecessor, Jo Cox, was murdered in June 2016 by a neo-Nazi.

However, the accompanying "programme motion", to get all stages of the bill completed in three days and thus before 31 October, was defeated by 322 votes to 308 after MPs objected that this would not allow time for adequate consideration.