A 'truckload' of gas needed to knock out Jenson Button

Jessica Michibata, with fiance Jenson Button

James Rothwell London

Anaesthesia experts have debunked claims that French robbers used sleeping gas on Formula One star Jenson Button and his wife during a burglary.

The 35-year-old racing star and his wife Jessica were feared to have been knocked out by gas pumped into their luxury villa on the French Riviera, leaving them helpless as thieves seized her £250,000 engagement ring on Monday night.