British Prime Minister Theresa May has pledged to put her heart and soul into the battle to persuade politicians in Parliament to approve the treaty she negotiated governing Britain's departure from the European Union.

Rejecting the deal would be risky and lead to division and uncertainty, she told members of the House of Commons in a speech yesterday. Her publicity campaign also included the publication of an unusual "letter to the nation", in which she appealed for support for the deal on Brexit, as the process of Britain's separation from the EU is universally known.