Boris Johnson goes on the attack after the Supreme Court ruled his suspension of the UK Parliament was illegal.

He accuses opponents of trying to "frustrate Brexit" and blames the court for making it harder to renegotiate the UK's Brexit deal with the EU.

Johnson will cut short his visit to the UN General Assembly in New York and return to London.

Opponents line up to call on him to resign.

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Boris Johnson has lashed out at the UK Supreme Court after it ruled that his decision to suspend Parliament was illegal.

Johnson's premiership was rocked on Tuesday after the UK's highest court found that his move to shut down parliament for five weeks was "extreme" and "unlawful."

Speaking to reporters in New York, where he is attending the UN General Assembly, Johnson accused his opponents of trying to "frustrate Brexit" and accused the court of wrecking his hopes of negotiating a new deal with the EU.

"I strongly disagree with this decision," Johnson said.

"I have the upmost respect for our judiciary [but] I don't think this was the right decision. I think that the prorogation has been used for centuries without this kind of challenge".

Watch: Boris Johnson says he 'strongly' disagrees with Supreme Court

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Read more: What happens now the Supreme Court has ruled Boris Johnson broke the law by suspending parliament?

Read more: Read the UK Supreme Court's explosive verdict on why Boris Johnson's suspension of parliament was illegal

He acknowledged that "of course parliament will come back."

However, he added that "let's be in no doubt there are a lot of people who want to frustrate Brexit.

"There are a lot of people who want to stop this country coming out of the EU."

He accused the court of making it harder for him to secure a deal with the EU.

"To be honest, it is not made much easier by this kind of stuff in parliament or in the courts," he said.

A spokesperson for the prime minister said he would not be resigning but would return home early in time to be back in Parliament on Wednesday.

The opposition Labour party moved to cancel the last day of their annual conference in Brighton, England, with their leader Jeremy Corbyn making his final address a day early on Tuesday afternoo disagreed