Labour have prematurely capitulated to Theresa May's government by vowing not to block a Brexit, according to Caroline Lucas. The co-leader of the Greens made the comments in reaction to a speech from John McDonnell today (15 November).

The shadow chancellor said Labour MPs would not oppose a vote on Article 50, the official mechanism to split from the EU.

The left-winger claimed such a move could put Labour on the side of "corporate elites".

But Lucas warned Labour would weaken opposition to a so called "hard Brexit" in the House of Commons by allowing the government to trigger Article 50.

"Though we should not seek to overturn the result of the referendum it is down to us as MPs to look closely at the deal on the table before throwing our support behind the government's plans," she said.

"A small majority of people voted to leave the EU, but without any clear plan of what such a vote would mean. I'd urge Labour to rethink their stance on this.

"The government should not be able to ride roughshod over parliament – and MPs should be demanding more details from ministers before standing aside and letting them pursue Brexit entirely on Tory terms."

May had promised to trigger Article 50 by March 2017, but the prime minister's plans took a blow when England's High Court ruled parliament must have a vote.

The government is planning to contest the decision at the Supreme Court, with a ruling expected in January 2017.

Number 10 was forced to distance itself from an "unsolicited", leaked memo to the government. The document, which was published in The Times newspaper, was reportedly drafted by an accountancy firm.

The memo claimed the government had no single Brexit plan and that Whitehall was working on 500 projects related to the issue, while needing to hire 30,000 extra civil servants.

"What we saw from the memo today simply confirms what we all suspected because of the various leaks that have been coming from the government already," McDonnell said.

"The issue is it isn't just about staffing, the memo is confirming what we knew, which is ministers arguing among themselves all the time, no common view of the way forward and no shared vision of the future for our country."