British Prime Minister Boris Johnson faced enormous pressure as the parliament re-opened Wednesday after the Supreme Court ruled his act to suspend the parliament for five weeks was unlawful.

The United Kingdom's Prime Minister Boris Johnson arrives to address the General Debate of the 74th session of the General Assembly of the United Nations at United Nations Headquarters in New York, New York, USA, September 24, 2019. [Photo: EPA via IC/JUSTIN LANE]

Johnson faced MPs in the House of Commons hours after the opening of the parliament as both the main opposition Labour Party and the Scottish Nationalist Party called for him to resign.

Johnson, for his part, accused opposition politicians of attempting to sabotage Britain's exit from the European Union (EU).

Politicians on the Conservative benches gave Johnson a lengthy and prolonged applause, cheering their support for the embattled prime minister.

Johnson said when he prorogued parliament he was following the same process as his Downing Street predecessors.

He said: "I think the (Supreme) court was wrong to pronounce on what is essentially a political question at a time of great national controversy."

"This parliament must stand aside and let the government get Brexit done or bring about a vote of no confidence and face the day of reckoning," the prime minister added.

Earlier Wednesday, Attorney General Geoffrey Cox defended the legal advice he had given to Johnson and his advisors about the right to suspend parliament.

Cox, who had also faced calls to resign, told the MP: "The Government accept the judgment and accept that they lost the case. At all times, the Government acted in good faith and in the belief that their approach was both lawful and constitutional."

Parliament had not been due to reopen until Oct. 14 following the shutdown which the British monarch had authorised on the request of the government.

After Tuesday's court ruling, Johnson cut short a visit to New York where he was attending a meeting of the UN General Assembly.