Some 4,700 people who tested positive for Covid-19 said they had attended Vision Nine’s 50,000-capacity Boardmasters festival in Cornwall or had connections to it.

Cornwall Council’s public health team is urging all residents and visitors to Cornwall to make testing a priority as the number of cases there continues to rise.

Following Boardmasters, which took place on the outskirts of tourist hotspot Newquay from 11-15 August, health officials said around three-quarters of the 4,700 people who had tested positive were aged 16-21, and around 800 live in the county.

Among the Covid mitigation measures adopted at the festival was the requirement for all attendees aged 11 and over to show proof of their Covid-19 status via an NHS Covid Pass confirming full vaccination, proof of a negative test result or natural immunity after a positive PCR test – taken at least 10 days earlier.

Camping ticket holders were required to bring NHS lateral flow tests with them, to take one during the event and log their results in the NHS Covid Pass. The wearing of face masks was not compulsory but encouraged.

Access attended Boardmasters and can confirm that the entry requirements were rigidly monitored, and that the vast majority of attendees were teenagers. Outside the festival Cornwall was unusually busy, even for August, with huge queues seen at many facilities.

The number of Covid infections in Cornwall and the Isles of Scilly has spiked significantly in recent weeks, with 717 cases per 100,000 of the population infected in the week ending 19 August.

Rachel Wigglesworth, director of public health for Cornwall and the Isles of Scilly, said Covid cases in Newquay were high before the festival: “Covid cases have been rising steadily across Cornwall over recent weeks – particularly in our tourist hotspots. This is an inevitable consequence of the lifting of restrictions and the Delta variant’s increased transmissibility. It is quite a different picture to last summer.

“Of course, big events and mass gatherings like Boardmasters are now permitted and our public health team worked closely with the organisers over many weeks to ensure the event was as Covid-safe as possible, with measures going above and beyond national guidance.”

A Boardmasters spokesperson said the event team had worked closely with Cornwall Council’s public health team and put in place risk management measures above and beyond national guidelines. As a result of the mitigation measures 450 people were detected as being at risk of passing on the virus and as a result were prevented from attending the festival or left the festival early.

The statement said, “No event is able to eliminate risk entirely and the latest Test & Trace data includes reported infections among the 76,000 people who visited the festival or related activities at Fistral Beach, in Newquay and the wider area during the week of Boardmasters. We will continue to work with our public health partners to understand the extent to which attendance at the festival has contributed to the figures. We look forward to sharing our experience with our local authority partners and other large events so we can all continue to provide much needed economic benefit to our communities and entertainment to our loyal audiences.”