Theresa May will face a new Brexit legal challenge if she fails to give the House of Lords a vote before triggering the process of leaving the European Union.

Gina Miller, the businesswoman leading a Supreme Court case to prevent the Prime Minister from triggering Article 50 without parliamentary approval, said that there must be a "proper debate" in the Lords.

She said that if she wins her case then the Government must introduce legislation that will have to pass through both the Commons and the Lords.