The British Prime Minister has no legal obligation to consult parliament on invoking Article 50 of the European Union's Lisbon Treaty to trigger the formal exit procedure from the bloc, a spokesman for Prime Minister Theresa May said on Tuesday.

He said May did not need to hold a parliamentary vote to initiate the formal divorce procedure.

According to media reports over the weekend, May had been advised by leading constitutional lawyers that she did not have to seek the approval of parliament before she triggers the Article 50 procedure that will make parting with Europe irreversible.

However, that won't stop a group of lawyers who have already mounted a legal challenge in a bid to force May to hold a parliamentary vote.

In October, the high court will hear lawyers argue that Article 50 cannot be invoked until the British Parliament's European Communities Act of 1972 is repealed.