Formula 1 racing driver Jenson Button and his wife Jessica Michibata were gassed until they were unconscious by robbers who then stole jewellery and other items worth about £300,000 from their holiday home in France.

Three friends who were staying in the house in St Tropez were also knocked out by a canister of anaesthetic gas dropped into an air vent.

Button and Ms Michibata had been asleep at the time, but because of the effects of the gas they did not wake up as the gang moved around the house and near their bed.

A source close to Button, 35, who won the F1 championship in 2009, told The Sun newspaper: “Police have told Jenson they’re convinced the burglars gassed the house using the air-conditioning units.

“Over the past five years, it’s becoming an increasingly common way for top criminals to launch raids on expensive properties in the area without being disturbed.

“Jenson is convinced that’s what happened too. The burglars were in the same room as him and Jessica, rifling through all their drawers.

“But they weren’t disturbed at all because the effects of the gas gives the burglars free reign.

“It was the same for their three other friends - they were all completely out of it.”

The occupants of the house only discovered what had happened when they woke up in the morning.

Ms Michibata’s £250,000 wedding ring was among the items stolen by the thieves.

A spokesman for the sports star said: “Jenson, Jessica and friends were on holiday in a rented villa.

“Two men broke into the property whilst they all slept and stole a number of items of jewellery including, most upsettingly, Jessica’s engagement ring.

“The police have indicated that this has become a growing problem in the region with perpetrators going so far as to gas their proposed victims through the air conditioning units before breaking in.

“Whilst unharmed, everyone involved is unsurprisingly shaken by the events.”

French police have blamed gangs of foreign criminals who target the wealthy people who visit or live on the French Riviera.