The event, which takes place at Burghley House near Stamford in Lincolnshire. was scheduled to take place from September 2 to 5.

Officials said that despite the continued easing of lockdown measures, the nationwide vaccination programme and the hope within the Government roadmap for unlocking the country, too many variables and uncertainties remained due to the ongoing COVID-19 pandemic.

A statement from organisers warned significant investment would be needed in the months leading up to the event, which would have severe financial implications should a cancellation have been required at a late stage.

"We have, throughout the last six months, striven to find an event scenario which would allow our competitors, followers, exhibitors and contractors to enjoy this annual sporting highlight," the statement read.

"However, the event runs on a greenfield site; the lead time and strategic infrastructure planning all require significant investment and expenditure year on year.

"Staging the competition element is ongoing 365 days a year, from one year’s event to the next and the contractual cancellation procedures mean that even though restrictions are easing across the country, we have to make difficult decisions many months ahead of the event.

"The severe financial implications of a potential cancellation of an event of this scale and magnitude at a late stage, without available pandemic insurance, are too great to risk for all involved."

It is the second time successive year the Burghley Horse Trials have been cancelled, with 2020 marking the first time the event had not been held since the first edition back in 1961.

The three-day event is one of is one of six annual CCI5* star horse trial events, along with the Badminton Horse Trials, the Kentucky Three-Day in the United States, the Australian International Three Day event in Australia, the Luhmuhlen Horse Trials in Germany and the Stars of Pau in France.

The competition is one of the three events which form the Grand Slam of Eventing, alongside the Kentucky Three-Day and Badminton Horse Trials.

The Kentucky Three-Day event was held last month following its absence in 2020.

The Badminton Horse Trials were cancelled for a second straight year amid the "fragile and unpredictable" coronavirus situation, which has led to Burghley suffering the same fate.

"It is with a very heavy heart that we have come to the extremely difficult decision to cancel The Land Rover Burghley Horse Trials this year," said Miranda Rock, President of Land Rover Burghley Horse Trials.

"The Horse Trials is an incredibly important part of what we do here at Burghley and is the highlight of the year for all those who live and work here.

"I am deeply sorry for everyone whose hopes have been dashed - from the equestrian world internationally to the pony clubs nationally, for the people of Stamford and our neighbouring communities, as well as our wonderful suppliers, supporters, retailers, staff and visitors who will not be able to enjoy this glorious event in September.

"Next year marks our 60th Anniversary and, despite the challenges ahead, we will be focusing all our efforts on delivering a spectacular event in 2022."

It is planned for next year’s event to take place from September 1 to 4.