"I kicked a heroin habit in New York City", Dylan confessed to critic Robert Shelton in March 1966, in a two-hour interview unearthed by the BBC.

"I got very, very strung out for a while, I mean really, very strung out. And I kicked the habit. I had about a $25-a-day habit and I kicked it."

The interview which took place on Dylan's private jet, flying from Nebraska to Denver, lasted two hours.

He also admitted that he was less than happy with his work "You can't be happy by doing something groovy".

"I'll admit to having this suicidal thing... but I came through this time."

The tapes were discovered during research for Shelton's revised biography, which is on sale tomorrow on Dylan's 70th birthday.