He was linked with the top bosses like Lucky Luciano, Al Capone's cousin Joseph Fishetti and Carlo Gambino.

According to various reports, Sinatra introduced John Kennedy to a call girl who allegedly had affairs with both the US President and Chicago mob figure Sam Giancana.

Sinatra's career decline and stunning resurgence are said to have served as the basis for Johnny Fontane in The Godfather (1972), whose floundering career is resurrected by Mafia muscle.

Sinatra denies Mafia connections to the Nevada Gaming Board

In 1963, the Nevada Gaming Board stripped Sinatra of his licence to do casino business in Las Vegas after he was seen entertaining mobster Giancana at a casino in Lake Tahoe.

A photograph of him with Mafia chiefs was shown to the Board, but he denied involvement with the Mafia.

The licence was restored in 1981, thanks in part to Sinatra's friendship with then-President Ronald Reagan.

Organised crime

Sinatra was so angry about reporters' questions about his alleged Mob connections that he sometimes got into brawls with the journalists.

Despite months of legal manoeuvres, Sinatra was compelled to testify at a New Jersey commission investigating organised crime in 1970.

Sinatra demanded an apology from a 1972 congressional committee after a witness in a crime inquiry claimed he was involved in the New England Mafia syndicate.

The inquiry heard that Sinatra had invested vast amounts of money in a renowned Mafia-controlled hotel and racecourse.

Prince Charles 'not impressed'

"I resent it," he told the hearing. "I'm not a second-class citizen. All I'm asking is for somebody to be fair about it."

But at a later hearing, Sinatra acknowledged having met Goetano Luchese, the former head of a Mafia family in New York.

In 1974, after meeting Sinatra, the British Prince of Wales said he was not impressed by the "creeps" and "Mafia types" with whom Sinatra hung around.

Prince Charles added that Sinatra was "a pretty strange person" who "could be terribly nice one minute and, well, not so nice the next".