Jeremy Corbyn has been accused of trying to “sabotage” Brexit talks that begin this week by setting Theresa May a near-impossible target if she wants Labour’s support for the final deal.

The Leader of the Opposition said Labour MPs would only vote for a deal if it guaranteed “unfettered access” to the European market - something that has already been ruled out by the EU.

By raising the prospect of a Parliamentary rebellion against the deal Mrs May secures, the Labour leader has given EU member states a stick with which to beat the Prime Minister as she tries to get the best deal for Britain.

On Wednesday Mrs May will open the way for two years of negotiations with the EU when she invokes Article 50, the formal process of withdrawing from the EU.