'Mad Frankie Fraser' in critical condition: Notorious Sixties gangster in a coma following leg surgery

The 90-year-old was known as a rival to the Kray brothers

Gangster Mad Frankie Fraser is in a coma, following surgery complications.

His condition is thought to have been caused by an operation on his fractured leg.

The 90-year-old, who served 42 years in prison, is in a critical condition at King’s Hospital in London, the Mirror reports.

The injury is believed to have occurred after Fraser had spent just two weeks in prison during the Parkhurst Prison riots on the Isle of Wight in 1969. He was considered one of the incident’s ringleaders and spent six weeks afterwards in hospital while he recovered from his injuries.

He was incarcerated over 26 offences and freed from prison in 1989.

Fraser was a member of The Richardson Gang, who were rivals to gangsters the Krays brothers. He was known for violently “punishing” those who owed money or who angered his bosses. During the “torture trial” of 1967, he was accused of pulling out his victims' teeth with pliers.

One of Sixties London’s most feared criminals, he earned the nickname “Mad Frankie” after he pretended to be mentally ill to avoid the World War II call-up. He was classified as insane three times during his prison stints.

Since leaving prison, he busied himself holding walking tours of famous gangland spots in the East End. He also featured in on television shows including Operation Good Guys, Shooting Stars and the satirical show Brass Eye.

Last year, at the age of 89, he was given an ASBO after an incident at his care home.