THERESA May has hit out at Boris Johnson’s ‘incompetence’ for signing up to the EU Withdrawal Agreement ‘without understanding it’. 

In a scathing speech in the House of Commons lthis evening, the former Prime Minister said the government had signed the agreement with the bloc “in good faith” less than a year ago, questioning why it did so if it was “so bad”.

She said that while elements of the UK Internal Market Bill affecting Northern Ireland borders (clauses 41 to 45) remain in the legislation. she would not be able to support it and accused the Prime Minister of acting “recklessly and irresponsibly”.

Addressing MPs, Mrs May said: “The Northern Ireland protocol [is] part of the withdrawal agreement, the withdrawal agreement that was signed by my friend, the Prime Minister, less than a year ago.

“I can say to the minister, that in my view clauses 41 to 45 have no place in this bill.  “Now, we’re told that they’re there because the EU either is, or might, act in bad faith, because the withdrawal agreement put a border down the Irish Sea, and the government can’t accept that.

“But the government did accept it when it signed the withdrawal agreement with the European Union...” She said she had concluded that “the government didn’t really understand what it was signing up to when it signed the withdrawal agreements.” 

The debate is the third day of discussions on the controversial trade bill, which the Scottish and Welsh government claim is an attack on devolution.

It passed its first round of scrutiny last week by 77 votes, and will be dated further before being put to the House of Lords.

Several senior officials, including the Advocate General for Scotland Lord Keen, quit in protest over the bill which Northern Ireland secretary Brandon Lewis said would break international law. 

Mrs May added: “I cannot emphasise enough how concerned I am that a Conservative government is willing to go back on its word to break an international agreements signed in good faith, and to break international law.

“Frankly, my view is that to the outside world it makes no difference whether the decision to break international law is taken by the Prime Minister or by his parliament, it is still a decision to break international law. 

“This can only weaken the UK in the eyes of the world. One of the great strengths we have as a country is our commitment to the rule of law, and this will have been damaged. 

“Our reputation as a country that stands by its word will have been tarnished, and the willingness of other countries to trust the United Kingdom, and its values will it be reduced. So much for global Britain.”

Finishing her address, she cited the action she took against Russian diplomats following the Salisbury poisonings, saying: “ I called on our friends and allies, I led the action that resulted in 29 countries expelling an unprecedented 153 Russian agents from their borders.

“We were able to do that, because those countries had trust in the United Kingdom. Where will that trust be In future?

“The government is acting recklessly and irresponsibly, with no thought to the long term impact on the standing of the United Kingdom in the world.  “This will lead to damage to the reputation. It puts the future of the United Kingdom at risk. And as a result, with regret, I have to tell the minister I cannot support this.” 

SNP Deputy leader Kirsten Oswald also took part in the debate, where she said Mr Johnson had failed to speak to devolved governments about the trade bill before it was presented.

She said: "The Prime Minister visited Northern Ireland last month, and talked of close cooperation between central and devolved governments. But he didn’t engage with anyone outside Westminster in the development of his bill. He excluded all of the devolved administrations from the process of developing a so-called single market for the United Kingdom.”

Ms Oswald described the legislation as “his shabby bill” and said: “Fundamentally, at its heart, this bill is ill-conceived, confused and very damaging, frighteningly like the UK Government. Neither of them deserve our support.”