The prime minister described the proposed legislation on Wednesday as “belt and braces protection against extreme interpretations of the [Northern Ireland] protocol.”

Concerns over protections for the Good Friday Agreement, which brought peace to Northern Ireland, are one of the main sticking points in objections to the Internal Market Bill.

Amid concerns rebel Tories would scupper the bill, Downing Street on Wednesday agreed to table an amendment to the legislation, giving MPs final say before a minister can breach the Withdrawal Agreement.

Johnson said he wants the legislation to protect Britain’s “territorial integrity” if trade talks with Brussels fail. Asked by Labour MP Hilary Benn if he believed the EU was negotiating with London in good faith, the prime minister said: “I don’t believe they are.” However, he added that it was “always possible that I am mistaken and perhaps they will prove my suspicions wrong.”

The EU has threatened the possible suspension of trade talks if the new British legislation is not withdrawn. President of the European Commission Ursula von der Leyen said on Wednesday that “with every day that passes, the chances of a timely agreement do start to fade.”

The divorce deal “cannot be unilaterally changed, disregarded or dis-applied,” von der Leyen said. “This is a matter of law, trust and good faith.”

Johnson also said on Wednesday if Britain were to set an external tariff regime with the EU, it would be “quite formidable” for some of the bloc’s products. “I think that’s even more reason why everybody should want to agree a zero tariff, zero quota arrangement,” he told a parliamentary committee.

Speaker of the US House of Representatives Nancy Pelosi has warned Westminster that Congress will block any US trade deal with the UK if Brexit imperils the Good Friday Agreement.

On Wednesday, Johnson responded to her statement, saying that he believes US politicians will “understand” the UK is trying to protect the Northern Irish peace process.