British Prime Minister Boris Johnson's Brexit plan was facing mounting legal, political and diplomatic challenges on Friday as Ireland accused Britain of being unreasonable and former British leader John Major sought to stop the suspension of parliament. 

But lawmakers who are seeking to block a no-deal Brexit are making it more likely that Britain leaves the European Union (EU) without a deal, Johnson said Friday.

Johnson has promised to lead the United Kingdom out of the EU in two months with or without a divorce deal, a threat he hopes will convince the bloc to give him the exit deal he wants. 

While German Foreign Minister Heiko Maas said Britain should make concrete proposals as soon as possible, the EU could not imagine reopening the Withdrawal Agreement that Johnson's predecessor Theresa May agreed with Brussels in November.

In the eye of the Brexit maelstrom, Johnson was under mounting pressure: opponents in parliament were plotting to tear up his Brexit plans or topple his government, while his suspension of parliament was under scrutiny in the courts.

With just two months until the leave, Johnson's decision to ask Queen Elizabeth II to suspend parliament was under challenge from three separate court proceedings. 

The Queen on August 28 approved Johnson's order to suspend parliament from as early as September 9 to October 14, a move that ensures parliament would sit for around four days less than it had been expected to. 

A Scottish court will hear arguments on September 3, a case brought by campaigner Gina Miller will be heard on September 5 and a Northern Irish court will hear a separate case on September 6.

Ultimately, the cases could be combined to go to the Supreme Court – the final court of appeal in the United Kingdom which hears cases of the gravest constitutional importance. 

In parliament, the battle for Brexit was due to begin in earnest on September 3 when lawmakers return from their summer break and will try to either topple the government or force through a law designed to prevent Britain leaving the EU without an exit deal.

Johnson's decision this week to suspend parliament for more than a month before Brexit has enraged opponents who have taken to the courts in Edinburgh, Belfast, and London to try to stop him. 

At a hearing in Belfast's High Court, Lord Chief Justice Sir Declan Morgan set September 6 for the presentation of legal argument on the interim injunction that is being sought by a rights activist seeking to have the suspension reversed. 

A more substantive case launched by the same activist, Raymond McCord, is due on September 16 against any withdrawal from EU without a divorce deal, citing fears that a chaotic Brexit could wreck the Northern Ireland peace process. 

"The Prime Minister wants to get his own way without concern for the people of Northern Ireland and the peace process," McCord, who was also behind a 2016 Northern Ireland challenge to Brexit, told reporters. 

Former PM joins the fray

Former British Prime Minister John Major has asked to join legal action to try to block current Prime Minister Boris Johnson from suspending parliament before Brexit.

Major, prime minister from 1990 to 1997, said he would join anti-Brexit campaigner Gina Miller in pursuing a judicial review of the order to close parliament.

"In view of the imminence of the prorogation – and to avoid duplication of effort, and taking up the Court’s time through repetition – I intend to seek the Court's permission to intervene in the claim already initiated by Gina Miller, rather than to commence separate proceedings," Major said.

"If granted permission to intervene, I intend to seek to assist the court from the perspective of having served in government as a minister and prime minister," he said in a statement.

(With input from Reuters, AFP)