Prime Minister Boris Johnson's government will seek to persuade Britain's top court this week that his decision to suspend parliament until shortly before the date for Brexit was not illegal as Scottish judges concluded last week.
Johnson announced on Aug. 28 that he had asked Queen Elizabeth to prorogue, or suspend, parliament for five weeks from last week until Oct. 14, saying the shutdown was necessary to allow him to introduce a new legislative agenda.
Opponents said the real reason was to prevent scrutiny and challenges by parliament where he now has no majority to his Brexit plans, especially his promise to leave the European Union by Oct. 31 even if no divorce deal has been agreed.
In a damning judgement, Scotland's highest court ruled last Wednesday that the suspension was unlawful and was an "egregious" attempt to stymie parliament.
However, a week earlier the High Court of England and Wales rejected a similar case, saying the matter was political and not one for judicial interference.
Both cases are now going before the Supreme Court, the highest judicial body in the United Kingdom, and its 11 judges will give a final ruling on whether Johnson's advice to the queen was illegal.
Supporters of the legal challenges, a mixture of anti-Brexit campaigners and opposition lawmakers, want parliament to be immediately recalled if the court backs them. Critics also say that if judges decide Johnson misled the monarch, then he must resign.
Johnson said the current session of parliament was longer than any since the English Civil war in the 17th century, adding that lawmakers would have plenty of time to again discuss Brexit after an EU summit on Oct. 17-18.
When asked on Friday if he had misled Elizabeth, Johnson said "Absolutely not". "Indeed, as I say, the High Court in England plainly agrees with us, but the Supreme Court will have to decide," he added.
The Conservative government say opponents of Brexit are using the courts to try to frustrate Britain's departure from the bloc which was backed by Britons in a 2016 referendum.
The Supreme Court ruled against the government in a similar constitutional case in 2017 when it said ministers could not begin the formal two-year exit process without the approval of parliament.
That case was led by investment manager Gina Miller, who is one of those taking on the government in the current legal battle along with former Conservative Prime Minister John Major.
The Supreme Court hearings will run until Thursday, with the verdict not expected until Friday at the earliest.