Former prime minister Sir John Major has joined the legal action being brought by Gina Miller over Boris Johnson’s decision to suspend parliament.
“I promised that, if the prime minister prorogued parliament in order to prevent members from opposing his Brexit plans, I would seek judicial review of his action,” said the former Tory leader.
Sir John said he wanted “to avoid duplication of effort” and” taking up the court’s time” so added himself to the anti-Brexit campaigner’s claim rather than launch separate proceedings.
“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, and also in parliament for many years as a member of the House of Commons,” he said.
Ms Miller later tweeted to confirm her challenge would be joined by Sir John – and revealed the case would be heard on Thursday, 5 September.
Labour’s deputy leader Tom Watson later said he would also join, calling the suspension of parliament “an unprecedented affront to democracy”.
He said: “I have taken advice on legislative solutions to challenge the prime minister’s action to stop us crashing out of the EU without a deal … I will be joining the judicial review launched in the High Court by Gina Miller and supported by John Major as a claimant.”
Meanwhile, a judge in Scotland has ruled against a legal bid to immediately block Mr Johnson’s move to prorogue parliament for over a month during the Brexit countdown. Court of Session judge Lord Doherty rejected a request to temporarily halt the shutdown, saying he was “not satisfied that it has been demonstrated that there's a need for an interim suspension”.
A court in Northern Ireland will still hear from lawyers representing anti-no deal campaigners challenging the prime minister’s move.
The slew of legal challenges was launched after the Queen approved Mr Johnson’s request for a five-week suspension from 10 September.
Another former prime minister, Gordon Brown, has accused Mr Johnson of “tearing the country apart” with no plan to bring people together again.
Mr Brown said the current inhabitant of No 10 is “shredding the constitution” with his prorogation manoeuvre.
The former Labour leader also said that the UK was being torn into pieces by “competing nationalisms” and that reconciliation will take “years if not decades”.
Speaking at the think tank Our Scottish Future, in Edinburgh, he added: “Leadership should be about healing divisions and not accentuating them.”
Additional reporting by PA
