In the corner of John Collins’s Surrey office, over the showroom from which he used to sell used Ferraris and next to the shelf that shows him collecting a polo trophy from the Queen, there are several guitars. One has markings that indicate it was once used by Carl Perkins. Another was played by Roger McGuinn of the Byrds. A 1952 Gibson Les Paul Goldtop once belonged to Frank Zappa.

Among these instruments is another, less impressive-looking piece. It’s a Rex with a sunburst finish and laminate top. There is nothing flashy about it and its worth (an estimated £100,000) is revealed only when you consider the extras it comes with. There are two photographs: one, from 1957, shows the guitar’s owner, Ian James, bare chested and be-quiffed, strumming it in his back garden. The picture was taken by his boyhood friend, Paul McCartney, who holds the instrument in the second photo and has provided a letter that confirms it was the first guitar he ever held.

It was also the instrument on which he learned his first chords, and James had it with him on the day the Beatle first met John Lennon at the Woolton church fete. Lennon may have handled it that night and James thinks it is possible George Harrison played it.

Collins, the Glasgow-born managing director of the auctioneers Cooper Owen, which is selling the guitar, has no doubt about the significance of the piece.

“The McCartney guitar is radical. He never poses for a picture or signs a letter of provenance on anything. That’s the guitar he played the chords on that so impressed Lennon, who then invited him to join the Quarrymen and the Beatles. Without that guitar, and the guy teaching him the chords, there might not have been the Beatles as we know them.”

Collins’s route into rock memorabilia was circuitous. He began his professional career as a copy boy on the Glasgow Evening Citizen. In 1968 he was made a trainee reporter after he went to work on his day off after hearing Robert Kennedy had been assassinated.

He moved to the Govan Press and the Kilmarnock Standard, then realised he could make more money if he took the photographs as well as writing the stories.

He learned photography at art school in Kent and dabbled with the rock’n’roll lifestyle as a soundman for the band Vanity Fare, before returning to Scotland to start a news agency.

He can still offer a checklist of his scoops, from photographing the rescue of Greenpeace activists during a seal cull off Orkney, to the exclusive shot of a car crash involving Princess Caroline of Monaco’s entourage when she was honeymooning on Arran in 1978.

As his interest in photojournalism grew, he covered the war in Beirut and the Pope’s visit to Ireland. His increasing wealth also allowed him to indulge his fondness for Ferraris.

Before long he was selling the vehicles — financing his purchase of £3m worth of cars on a deal that would have cost him his house if it hadn’t come off. After two years, Collins had a £30m turnover. He sold the company in 2000.

Since forming Cooper Owen a year ago with his friend, the singer-songwriter Louise Cooper, Collins has handled some of the most intriguing rock memorabilia. Prior to forming the company he owned a pair of John Lennon’s glasses and the guitar used by Elvis Presley’s guitarist Scotty Moore.

He reaches for a photograph. “That’s me with Scotty Moore,” he says. “I had his Gibson L-5. I regret selling it. I sold it for £300,000 when, God, it was priceless. That was the main guitar — his favourite. The L-5 was the sound that cracked Elvis on Mystery Train. It was really important. I had bought it to be used on some sessions with Louise, and being a typical dealer I sold it.”

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