UK’s parliamentary speaker John Bercow has warned Prime Minister Boris Johnson not to disobey the law by refusing to ask for a Brexit delay.

Mr Bercow also promised to hinder any attempt by Mr Johnson to circumvent legislation.

Speaking at the House of Commons on Thursday night, Mr Bercow said he was prepared to allow “additional procedural creativity” if necessary to allow parliament to block Mr Johnson from ignoring the law against a no-deal Brexit.

He said that if the prime minister looked as if he were trying to engineer a no-deal Brexit, he believed parliament would want to cut off that possibility.

Mr Bercow added: “Neither the limitations of the existing rulebook nor the ticking of the clock will stop it doing so.”

Challenging Mr Johnson and his cabinet, Mr Bercow said: “The only form of Brexit that we have, whenever that might be, will be a Brexit that the House of Commons has explicitly endorsed.”

He also proposed a written constitution for the UK to stop what he called “executive malpractice or fiat”.

The speakers intervention is, to say the least, highly unusual.

His comments came after Mr Johnson denied he had lied to the Queen when requesting a suspension of parliament this month.

Mr Johnson had written to the Queen asking to prorogue (suspend) parliament for five weeks from last Tuesday, claiming the suspension was necessary ahead of rolling out a new domestic agenda.

The unusually long suspension was widely seen as a bid to thwart opposition to a no-deal departure on 31 October Brexit date, and provoked uproar across the political spectrum as well as legal challenges.

When asked yesterday if he had misled Queen Elizabeth over his motives for the suspension, which will see the House of Commons closed until 14 October, Mr Johnson said: “Absolutely not”.

Meanwhile in Brussels, EU chief Brexit negotiator Michel Barnier said there was “no reason to be optimistic” about striking any divorce deal with Britain before a crucial 17-18 October EU summit.