LONDON, Sept. 13 (Xinhua) -- John Major and Tony Blair, two former British prime ministers, have teamed up to accuse the current Prime Minister Boris Johnson of "shaming" Britain by proposing legislation which undermines his own Brexit deal, local media reported Sunday.

The two former prime ministers, who unsuccessfully opposed Brexit in the 2016 referendum, claimed in their article carried by the Sunday Times newspaper that Johnson's UK Internal Market Bill will "jeopardise peace in Northern Ireland, make it harder to negotiate trade deals and destroy trust in Britain."

Their statements came just one day before the Internal Market Bill, which was published by the British government on Wednesday, is to be debated in the House of Commons (lower house of parliament) on Monday.

The bill overrides key elements of Johnson's Brexit deal with Brussels, despite a senior minister explicitly acknowledging that the plan would breach international law.

It is intended to ensure Northern Ireland can continue to enjoy unfettered access to markets in the rest of Britain, according to the British government.

Major and Blair also urged MPs to reject Johnson's attempt to override parts of the Brexit deal, calling "this way of negotiating...is irresponsible, wrong in principle and dangerous in practice."

Johnson is facing mounting criticism over the Internal Market Bill as leaders from across the political spectrum raised grave concerns over breaking the international law and damaging Britain's reputation, according to local media.

Leader of the opposition Labour Party, Keir Starmer, accused Johnson of having "reigniting old rows" by working to flout the Withdrawal Agreement, but pledged Labour support if he addresses "substantial" concerns.

Meanwhile, senior Conservatives were not backing down on their rebellion against the prime minister's plans despite his warning that the European Union (EU) could "carve up our country" without the bill.

Tory rebels suggested their numbers were growing and opinions were only hardened by Johnson's increased rhetoric that the EU could impose a trade border in the Irish Sea.

Despite the criticism, British Cabinet Office Minister Michael Gove on Friday defended the new bill, saying Britain had made clear during discussions with EU officials on the UK Internal Market Bill that legislative timetable for the bill would continue as planned.

Gove also reiterated the government's commitment to implementing the Brexit Withdrawal Agreement, including the protocol covering Northern Ireland.