Metal music fans heading to the mosh pits of Download festival this weekend are being urged to put their wearable technology into airplane mode to avoid making accidental 999 calls.

Over a routine weekend, Leicestershire Police handles about 600 emergency calls, and a further 800 calls to 101.

But when Donington Park hosts the three-day rock festival, this can leap up by almost 700 calls as people’s bodyworn devices such as smart watches “assume they have been in a collision”.

The “significant increase” in calls places a huge burden on handlers and can take resources away from genuine emergencies, the force said.

People attending the festival, headlined by Green Day, Sleep Token and Korn, are being asked to put their devices into airplane mode before entering mosh pits.

Each call to 999 has to be assessed, police said, so people who do make unwanted 999 calls are asked to stay on the line to confirm they are safe.

A spokesperson said: “All calls had to be assessed, with three outbound call attempts completed to ensure there is no threat, risk or harm, taking our contact handlers away from answering true emergency calls.”

Gates to campsites at Donington Park, near Castle Donington in Leicestershire, opened on Wednesday ahead of the three-day event over the weekend.

Festival organisers said they expected to host about 75,000 rock fans.