A man in his 30s was killed when an outdoor stage raised in a Toronto park for a concert of the British group Radiohead collapsed, police said Saturday.

"Shortly after 4 pm, a partial piece of stage at Downsview Park collapsed," a Toronto police spokesman said. "There is one person deceased."

According to reports, the deceased was Scott Johnson — a British national and sound technician with the band.

Three other people were injured, including a man in his 40s who was admitted to hospital.

The accident struck at Downsview Park about three and a half hours before the show was to start.

The concert was cancelled and officials opened a probe into the cause of the accident. Contrary to early speculation, there were no strong gusts of wind at the time the stage collapsed.

The victims were all part of a team installing projectors and speakers on the stage and on the metal scaffolding above the stage.

Police said that the accident took place one hour before ticketholders were allowed to enter the grounds — but could have been much worse had a crowd been there and panicked.

According to Radiohead's official website, the Toronto concert was sold out. Downsview Park can accommodate up to 40,000 spectators.