The 49-year-old Italian was due to ride Lord North at the Ebor, which begins on 19 August.

"I'm gutted to be missing York - but I can't stop the government doing what they want to do. I've decided to go to France instead," Dettori said. "I had to make a decision - they are two very good horses."

The British Horseracing Authority confirmed riders must self-isolate for 14 days on their return from France or use the elite athlete exemption rule - which requires two coronavirus tests seven days apart.

Dettori will ride the John Gosden-trained Mishriff in Saturday's Group Two Prix Guillaume d'Ornano and the unbeaten St James's Palace Stakes winner Palace Pier in the Group One Prix Jacques le Marois on Sunday.

"With Enable not running and Stradivarius not running at York, it made my decision a lot easier," the veteran jockey added. "Obviously Lord North is a good horse, and I'll be missing him, but the prize money in France is unbelievable".

Dettori rode Enable to his record third King George at Ascot win in July. Gosden says he hopes James Doyle will ride Lord North in the Juddmonte International at York, having steered him to victory in the Prince of Wales's Stakes at Royal Ascot in June.