John Bercow has warned Theresa May he will block any attempt to schedule a third meaningful vote unless she makes substantial changes to the motion being voted on by MPs.

In a major intervention, the Speaker of the House of Commons told MPs that he would rebuff any attempt to bring back the same motion unless there were “substantial” changes made to it.

Addressing the Commons in a hastily arranged statement, Mr Bercow said that he had permitted a second vote on the deal because significant changes had been made to during subsequent negotiations between the Government and Brussels.

These included three new documents and legal clarifications won by Mrs May, which he claimed could be considered “binding” and therefore substantial.

However, amid rumours that the Government is planning to bring the deal back to the Commons for a third time this week, Mr Bercow said he would now scrutinise any new motion to determine whether or not it had changed substantially.