Covid-19 forced the 2020 British Speedway Premiership to be cancelled
Swindon Robins have confirmed they will not compete in British Speedway's Premiership this year.
The 2019 champions say Covid-19 uncertainty around the sport and redevelopment of their Abbey Stadium this summer are behind the decision.
British Speedway will plan for the new season with only six teams and look to accommodate Robins riders elsewhere.
"We cannot dress it up, this is a blow to planning for the 2021 season," chairman Rob Godfrey said.
The British Speedway season normally begins in March, but organisers are understood to be targeting a May start for this year.
"Contrary to Swindon's concerns over sport going ahead this year, as a sport we are pressing ahead and going racing this spring and summer," Godfrey said.
"The vaccination programme is very encouraging and we are in no doubt we will be in for a good summer."
But Robins chairman Terry Russell is concerned speedway will struggle to operate without full crowds being permitted at some point in 2021.
"The economics of the sport, which relies so much on the paying spectator, are not robust enough to take any downturn in revenue particularly after the cancellation of the 2020 season," he said.
"Our government is not able to provide any indication of the timing or the steps of lifting the restrictions, which is not a criticism, just a fact.
"With this in front of us, it is impossible to plan and commit for racing at the Abbey in 2021."
Team manager Alun Rossiter told BBC Radio Wiltshire riders were fully supportive of the decision to stand down this season.
"Sometimes we have to make big and probably unpopular decisions in times like these," he said. "But we have to think about what's better for the club.
"We're in a good financial position, we don't currently owe anyone money and going into a season potentially haemorrhaging money is something we can't afford.
"I'm absolutely gutted, but I understand the full reasons behind it."
