British lawmaker and leading Brexit campaigner Boris Johnson said "of course" he will stand to be the next prime minister after Theresa May announced her resignation.

Speaking at a conference in Switzerland hours after May said she would leave next month, Johnson paid tribute to May, saying she was "patient and stoical" facing all the difficulties around the country's departure from the bloc.

The next British prime minister can also revive stalled talks with the EU over an exit deal, Johnson said. "A new leader will have the opportunity to do things differently and have the momentum of a new administration," he said.

"The verdict of the people has been lost and muddled in the parliamentary process."

"We are at a very interesting point in our political history," he said, before joking that it turned out to be a very good day to be out of London.

Johnson has been cited as the clear favourite to replace his former leader.

- Reuters