THEY'RE the long-lost concerts that Bob Dylan's diehard Scottish fans thought they would never hear.

Two shows from his incendiary, confrontational 1966 tour - one in Glasgow, the other in Edinburgh - are being released next month as part of a mammoth, 36-disc boxset.

Many dates on the tour were marred by audience catcalls and walkouts, prompted by fans' anger that Dylan had been a "traitor" to acoustic folk music, coming out in the second half of every show with the all-electric band who became, well, The Band.

The protests reached a low point when a waiter pulled a knife in Dylan's hotel room in Glasgow and stabbed his bodyguard in a fight. The touring bus was also broken into and recording gear stolen.

This was just two days after a fan at Dylan's Manchester show had famously yelled 'Judas!', a protest met by a contemptuous response from Dylan. "I don't believe you," he spat back, "you're a liar."

The boxset, Bob Dylan: The 1966 Live Recordings, which will sell in the UK at around £120, features every song played on that tour, starting in Sydney and ending in London. The "overwhelming majority" of the contents have been unreleased in any form until now.

Disc 21 of the set focuses on the May 19 show at the Glasgow Odeon and discs 22 and 23 concentrate on the following night's concert at Edinburgh's ABC Cinema. Both were sold out.

Adam Block, President of Legacy Recordings at Sony Music Entertainment, said: “While doing the archival research for last year’s box set of Dylan’s mid-60s studio sessions, we were continually struck by how great his 1966 live recordings really are.

“The intensity of Bob’s live performances and his fantastic delivery of these songs in concert add another insightful component in understanding and appreciating the musical revolution [he] ignited some 50 years ago.”

The tour came during a remarkable 18-month spell during which Dylan released the albums Bringing It All Back Home, Highway 61 Revisited and Blonde On Blonde, a trilogy which, in Legacy's words, secured his reputation "as a songwriter and performer of unprecedented depth, power and originality while significantly impacting the course of popular music and culture."

It adds: "These concert recordings from the same period document Dylan’s evolution as an on-stage phenomenon whose transformative vision saw no limits."

Dylan, however, had alienated many of his hard-core acoustic folk fans by going electric the previous year.

In Martin Scorsese's 2005 documentary, No Direction Home, drummer Mickey Jones recalled: "It really was pretty revolutionary in the fact that here was someone who everyone loved, and they didn't like what he was doing - and they were showing it ... When we kicked off the second half, we did kick ass and take names."

The 'Judas!' climax at the Manchester concert has been described by author Peter Doggett as a "piece of 1960s folklore."

In his bestselling book Electric Shock he says: "It documents a confrontation between audience members who had convinced themselves, against all aural evidence, that Dylan was only valid with an acoustic guitar, and a man who had staked his sanity on living with extremes, among them the crushing volume of an electric band."

Dylan arrived in Glasgow only to find that there was no escape from angry fans even in his hotel room.

In his book Behind the Shades, Clinton Heylin quotes Dylan's chauffeur-bodyguard Tom Keylock as saying that a waiter who had brought food to the room suddenly blurted out, "F--- him! I want to talk to him!", telling Dylan: "You're a f------ traitor to folk music!" Keylock said: "I shoved open the door and shoved him out. He pulls a knife on me - I've still got the scar to prove it - so I give him a good kicking."

Another Dylan author, Robert Shelton, wrote that the Glasgow show was marred by hecklers and walkouts. One fan called out: "We want Dylan," to which the singer responded: "Dylan got sick backstage. I'm here to take his place."

A contemporary review, however, made no mention of any walkouts, observing that the "capacity audience clapped, stamped and cheered" between numbers. In the second half, "the self-appointed king of contemporary folk ... let fly with some up-tempo numbers, almost verging on rock."

During the concert, someone broke into the band's private touring coach and stole recording and hi-fi gear, prompting enquiries by Northern Division CID.

In Edinburgh, the audience was again divided. One reviewer said Dylan was booed off the stage and some audience members took out mouth-organs and tried to drown out his singing.

Dylan turned 25 just four days later.

Much has been made not just of the relentless pressures he faced on the tour - playing concerts, giving press conferences, being filmed or interviewed - but also of Dylan's drug intake at the time, with Heylin writing that he was on a regime of heroin and 'speedball' - heroin plus coke or speed.

The world tour finished in London on May 27. Back home two months later, he had a motorbike accident, and disappeared from touring for eight years, although he wrote prolifically with The Band at their house, Big Pink, at Woodstock in upstate New York.

In the Scorsese documentary, Dylan said: "The guys who were with me on that tour ... we were all in it together, and we were putting our heads in the lion's mouth. I had to admire them for sticking it out with me. Just for doing it they were, in my book, gallant knights, for even standing behind me."

* Bob Dylan: The 1966 Live Recordings will be released on November 11.