London mayoral candidate Rory Stewart has dropped out of the race after the coronavirus crisis forced a year’s delay.
The former Tory cabinet minister said it was impossible to ask unpaid campaign volunteers to work for another 12 months.
The independent candidate said it had been an “agonising decision” for him to make.
The announcement comes on the eve of what would have been polling day.
The former MP for Penrith and The Border left parliament in October 2019 to run as an independent candidate.
He had campaigned for the Conservative leadership last summer.
But after Boris Johnson became prime minister, Mr Stewart was one of 21 Conservative MPs expelled from the party for rebelling over Brexit.