Theresa May stunned the House of Commons with a brutal takedown of Boris Johnson's Brexit bill.
Addressing Northern Ireland secretary Robin Walker, the former prime minister said:
I'm very grateful to my honourable friend for giving way. He's been setting out through his speech that the government wants clauses 41 to 45 because of the bad consequences that could come from the interpretation of the Withdrawal Agreement.
If the potential consequences of the Withdrawal Agreement were so bad, why did the government sign it?
The government are attempting to alter some elements of the Withdrawal Agreement which the UK co-signed with the EU earlier this year and which Boris Johnson repeatedly dubbed an "oven ready" Brexit deal ahead of December's general election. If the government fail to come to an agreement with the EU on the exact terms of these changes – a feat for which they now have less than four months – the UK will once again be faced with the prospect of crashing out of Europe without a deal.
The Internal Markets Bill, which has already passed through the House of Commons twice and has now reached committee stage, is what will allow the government to bypass some parts of the Withdrawal Agreement and, in doing so, break international law. Theresa May is one of five ex-prime ministers who have opposed this bill: David Cameron, Gordon Brown, Tony Blair and John Major have all also spoken out against it.
May drew particular attention in her speech to clauses 41 to 45, the section of the bill which addresses Northern Ireland protocol. How to ensure trading between Northern Ireland and the Irish Republic does not undermine the Good Friday Agreement, which effectively brought about peace along the Irish border, has been a major element of Brexit's complexity. Failure to do so in a way that satisfied both the UK and the EU was also part of the reason May repeatedly failed to negotiate a Brexit deal of her own between 2016 and 2019.
People are praising May's speech in the Commons.
While it's "extraordinary" for a recent prime minister to rebel against her party, May gave "one of the great speeches of this parliament".
Elsewhere in her speech, May described the Internal Markets Bill as "reckless and irresponsible" and laid out the reasons she cannot support it.
Risking the Good Friday agreement, damaging the UK's reputation and breaking international law were among the reasons she listed.
May was described as coming down "on the right side of history".
Her speech was even praised by some Labour MPs.
But not everyone was so forgiving.
May has previously abstained from voting on the Internal Markets Bill. It remains to be seen whether she will actively rebel against her party and vote against it – but this remains unlikely.
If the bill passes the committee stage in the Commons, it will graduate to the House of Lords before it can be enshrined in law.