Long known to have nurtured leadership hopes, Mrs May - whose friends recall her early ambition to be the UK's first female PM - could have reasonably expected to have had to wait until at least 2018 to have a shot at Downing Street.
STONEHOUSE, ENGLAND - JUNE 08: Vote Leave supporters pose for a photograph as they campaign on a residential housing estate in Stonehouse on June 8, 2016 in Gloucestershire, England. Britain will go to the polls in a referendum on the 23rd of June to decide whether or not to leave the European Union. (Photo by Matt Cardy/Getty Images)
PicturedL Theresa May's whirlwind first week in office
Theresa May was advised by a team of senior aides as she travelled to meet Nicola Sturgeon.