Former Prime Minister Theresa May has criticised her successor Boris Johnson over reports that he plans to renege on the already-agreed Brexit withdrawal treaty.
Theresa May hit out as it became public that Jonathan Jones, the head of the government’s legal department, is leaving his job over reported plans to undercut the Brexit deal and its Northern Ireland protocol.
The fallout was also felt in financial markets, with the pound sinking on Tuesday, following reports in the Financial Times that Mr Johnson could override the Withdrawal Agreement treaty.
The furore over the already-agreed treaty comes as Britain and the EU restart trade talks for life post-Brexit.
In the House of Commons, Ms May asked how the UK could be trusted when it signs future international agreements.
“The United Kingdom Government signed the withdrawal agreement with the Northern Ireland protocol. This parliament voted that withdrawal agreement into UK legislation.
“The government is now changing the operation of that agreement.
“Given that, how can the government reassure future international partners that the UK can be trusted to abide by the legal obligations of the agreements it signs?” she said.
The government has confirmed it will introduce a new bill on Wednesday that could change customs plans but denies that it effectively rips up the Brexit agreement.
The FT said Britain was considering tinkering with the deal's special arrangements for Northern Ireland which aim to avoid creating a hard border with the Irish Republic and allow trade to flow while protecting the bloc's internal market.
The border is the only land border between the UK and the EU after Brexit, and any attempts to alter the agreement will be watched carefully in Dublin.
Northern Ireland Secretary Brandon Lewis admitted the plan did break international law but insisted it was a "very specific and limited way".
Another Conservative MP, Tobias Ellwood, tweeted: "Britain's soft power and respected voice on the international stage comes from our duty & resolve to defend & uphold international laws."
Unnamed sources close to Mr Jones, the head of the Government Legal Department, said he was "very unhappy" with the decision to overwrite parts of the Northern Ireland protocol, the FT reported.
Britain has said it was committed to the Withdrawal Agreement treaty, but that it needed minor clarifications to support the 1998 Northern Ireland peace deal.
Sterling took a dive on Tuesday over the suggestions that Mr Johnson was threatening to override the divorce deal.
The clock is ticking on an October deadline for a trade deal and the end of the transition arrangement in late December.
After several months of rallying against the dollar, the sudden return of fears of a no-deal Brexit have frightened investors and knocked the pound 4 cents lower versus the dollar since the start of the month.
The pound dropped just over 1 per cent to $1.3034, its weakest since August 13.