British MPs and peers will return to parliament within hours for what is likely to be a fiery sitting following the Supreme Court ruling that its suspension was unlawful.

British PM Boris Johnson, who was in New York when the court handed down its ruling, carried on with his planned schedule on Wednesday – attending a business breakfast in Manhattan and then heading to the UN to meet world leaders, including Donald Trump and Iran’s Hassan Rouhani.

He gave a speech to the United Nations at 10pm New York time, before leaving for London. There, he is expected to face the music in parliament, amid reports he has apparently already spoken to the Queen.

Some of the many and varied reactions to Boris Johnson's UN speech pic.twitter.com/3AOc9RUizo

— Tara Mulholland (@tara_mulholland) September 25, 2019

Media in Britain report that a government source has confirmed Mr Johnson telephoned the Queen from New York, but refused to say if he had apologised to her – as some critics have called for.

Conversations between prime ministers and the monarch are considered private, and details are generally not released.

Mr Johnson has also reportedly spoken to his Cabinet following the 11-0 judgment by Britain’s highest court – described by some as “a legal earthquake” – that he misled the Queen in asking her to prorogue parliament for five weeks ahead of the Brexit deadline on October 31.

The BBC says it has been told by a source that the Leader of the Commons, Jacob Rees-Mogg, told cabinet ministers on the call that the Supreme Court’s ruling amounted to a “constitutional coup”.

The Prime Minister, who faces mounting calls to resign, has said he “profoundly disagreed” with the court’s decision but would respect it.

Calls for Mr Johnson to resign have come from Scotland’s First Minister, Nicola Sturgeon, Wales’ First Minister, Labour’s Mark Drakeford, and Sinn Fein’s vice president, Michelle O’Neill, as well as British Labour leader Jeremy Corbyn.

Liberal Democrats leader Jo Swinson said the judges’ decision proved Mr Johnson was “not fit to be Prime Minister”.

Wednesday's national newspaper front pages | UK News | Sky News https://t.co/sFd9NVrkMG

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Brexit Party leader Nigel Farage also wants Mr Johnson’s chief adviser, Dominic Cummings, to be sacked, adding: “The calling of a Queen’s Speech and prorogation is the worst political decision ever”.

Meanwhile, outgoing House of Commons Speaker John Bercow, who quickly called parliament back after the Supreme Court announcement, has said there will be “full scope” for urgent questions and ministerial statements when MPs and peers return on Wednesday.

The fallout from the court’s decision means Mr Johnson is likely to be tied down with regular parliamentary business, as well as having to answer MPs’ questions about Brexit.

His brinkmanship strategy of pushing Brexit negotiations as close to the October 31 deadline as possible looks to have become quite a bit more difficult.

In other deadlines, Mr Johnson is also scheduled to make the closing leader’s speech for the first time at the Tory party conference; the conference is due to start on Sunday. However, there is speculation it might be cancelled after this week’s parliamentary uproar.

There is also a looming EU summit on October 17-18.

-with AAP