The Bath Half Marathon has been postponed until next year.
The event was due to take place on Sunday 5 September after being postponed from March.
However bosses have said because of continued uncertainty around mass gatherings, coronavirus passports and highways infrastructure projects planned in Bath city centre, holding off for another six months is the best thing to do.
The event, which is one of the longest-running races in the UK and the biggest fundraising event in the West Country, is now scheduled to take place in March 2022.
The race came under scrutiny in March 2020 when bosses made the decision to go ahead with the event despite an official lockdown looming as coronavirus cases in the UK began to rise.
Race director Andrew Taylor has said without the answers they need to plan the 2021 event now, it leaves them with "insufficient time" to put it together.
Mr Taylor said in a statement: “With just over four months now before our event date we still do not have clarification from government on key factors such as whether social distancing will be required, whether spectators will be permitted and whether participants will be required to provide certification of Covid status.
"These factors will fundamentally effect how we deliver our event, and without this clarification we do not feel we have sufficient time now to plan our arrangements, or to carry out proper consultations with the council and other stakeholders, or to tender and place the necessary contractors’ orders."
He added organisers feel restrictions would "change the community character" of the event.
Highways projects would also have had an impact on the event in September, including repairs to Cleveland Bridge which is a key part of the diversion route around the city during the event road closures.
Mr Taylor said he is "particularly disappointed" for the thousands of runners who take part and the organisations and charities who rely on event like the Bath Half for crucial funding.
He added: "It’s heartbreaking to have to postpone our Bath Half Marathon for a second time and we know that many people will be disappointed by this decision.
"Sadly the combination of uncertainty surrounding continued Covid restrictions for large-scale events and planned infrastructure projects on the highways network in the city this autumn have left us with no choice."
He said he is confident the event will be able to go ahead in March next year to mark its 40th anniversary.
The Bath Half Marathon is the largest sporting and community event in the city and the largest charity fundraising event in the South West, raising £30million pounds for charity in the 20 years since Running High Events took over its management.
Its 140 charity partners who stand to lose around £2.5million pounds this year in fundraising, at a time when demand on the charity sector and the cost of service delivery have both significantly increased, due to the coronavirus pandemic
In a joint statement, Bath RUH Forever Friends Appeal, Dorothy House Hospice Care and Jamie’s Farm said: "The funds raised for local charities through the Bath Half are critical to our services in our community, and now with the challenges presented by the Covid-19 outbreak these funds are even more essential to keep our vital services going."
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