The Brighton Half Marathon has been postponed because of the delay to the end of lockdown restrictions, the organisers have announced.
Race bosses said the race, due to be held on 27 June, "did not fit the criteria" for it to go ahead under Step 3 rules.
They said they were "disappointed" at the postponement, but announced the race will now be held on 10 October.
The 2020 race, held before the pandemic began in February, saw more than 7,000 runners take part.
But race organisers said that under Step 3 restrictions, which the Prime Minister has extended till at least 19th July, events larger than 4,000 people cannot take place.
They said that it was "simply not possible" to "run the event on that basis."
"When the roadmap was announced, our planning was focused on delivering an event against the roadmap timetable for moving from Step 3 to Step 4 on June 21st," the half marathon team said.
"The size and open access nature of our event plus the number of crowds we attract does not fit the criteria to allow us to proceed."
The Brighton Half Marathon said that all runners who had a place in the June event will be automatically moved to the new date, 10 October.
But they runners would also be able to transfer their place to a friend or family member, move to the February 2022 date or run a "virtual half marathon" on the original date to claim a winners medal.