Charles Sobhraj, whose reputation as a disguise and escape artist earned him the nickname, was serving two life sentences in Nepal for the murders of Connie Jo Bronzich and Laurent Carriere in 1975.

Sobhraj, 78, was driven out of Central Jail in Kathmandu on Friday in a heavily guarded police convoy to the immigration department.

From there he was taken to Kathmandu airport and left the country on board a flight to France.

The country's supreme court had ordered his release on the grounds of poor health, good behaviour and having already served most of his sentence.

The Frenchman is believed to have killed at least 20 people in Afghanistan, India, Thailand, Turkey, Nepal, Iran and Hong Kong during the 1970s.

He is thought to have mostly targeted young backpackers on the hippie trail and also became known as the Bikini Killer as the bodies of several female victims were found in swimwear.

Sobhraj was jailed in Nepal in 2004 after being spotted at a casino in Kathmandu and arrested.

He had previously spent two decades in Delhi's maximum-security Tihar prison, but the trial in Nepal was the first time he had been convicted of murder.

Thailand issued a warrant for the arrest of Sobhraj in the 1970s on charges of drugging and killing six women, all wearing bikinis, but he was jailed in India before he could stand trial on those charges.