They are some of the most intimate images ever taken of John and Yoko. In one portrait, the couple are pictured at their secret wedding in Gibraltar in 1969. In another, they happily nestle together in the back of a limo following the ceremony.

Others show the newlyweds, both in white, looking relaxed on a private jet at the end of the wedding saga that would later be immortalised in hit song The Ballad Of John And Yoko.

Yet they are among the most controversial pictures, too. For as John Lennon’s widow prepares to mark the anniversary of her wedding to the late Beatle next Sunday, The Mail on Sunday can reveal these exclusive images are a source of anguish that has distressed her for decades.

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Stolen moments: John Lennon and Yoko Ono at the registry office during their 1969 wedding in Gibraltar

As the photographer who took the pictures that day explains, they are at the heart of a long-running mystery after vanishing in an apparent burglary. And, despite the best efforts of detectives, have never been seen since. Until now – because a Mail on Sunday investigation has tracked down the negatives for the 118 missing pictures, estimated to be worth more than £100,000, and discovered they are being touted for sale, apparently by well-known Beatles biographer, although he denies it.

Thailand-based Geoffrey Giuliano, put our reporter - who was posing as a collector - in touch with a mysterious middleman who offered to sell the negatives.

After sending over the contact sheet as proof he had the negatives, using Giuliano's email address, the 'middle man' demanded a cash transfer into his account – but then pulled out of the deal after suspecting the buyer was acting for Ono.

Just wed: John and Yoko with their marriage certificate. The pictures of the couple's wedding were at the heart of a long-running mystery after vanishing in an apparent burglary in 1975

He raised further questions about the legitimacy of the sale by claiming the original photographer is dead. David Nutter, however, is very much alive, and when contacted by the MoS was furious to learn his images were being sold without his permission. Speaking from his home in New York, he said: ‘It’s heart-breaking. It was the most important assignment for me… I’m so angry.’

It was just a few months before the release of the Beatles’ album Abbey Road when David, then 30, was summoned by the band’s Apple Corps executive Peter Brown and dispatched on ‘a top secret mission’. David had become part of the Fab Four’s trusted inner circle thanks to his brother Tommy, who was a tailor to the stars.

Soaring: A contact strip shows the couple relaxing in a private jet with Apple Corps executive Peter Brown

Love Me Do: The happy newlyweds in a limo after their secret marriage ceremony in Gibraltar

David recalled: ‘He asked me to get on the next flight to Gibraltar. But he wouldn’t tell me why. He just told me to take my camera.’

Desperate to avoid the London paparazzi, Lennon and Ono had wanted to seal their nuptials in a private ceremony. After failing to do so on a cross-channel ferry and also Paris, they had been advised to do it in Gibraltar, where, as a British citizen, Lennon could wed immediately.

Yoko is preparing to mark the anniversary of her wedding to the late Beatle next Sunday

‘The ceremony was very short,’ said David. ‘They let me do whatever I wanted. The important picture would be in the registry office. Them standing there and doing the vows.’

Yet the tale of David’s remarkable coup turned to disaster in 1975 when he lent his negatives to Anthony Fawcett, a former assistant to Lennon, to be used in Fawcett’s book John Lennon: One Day At A Time.

‘When I asked for the negatives back, he told me his apartment had been repossessed and everything had been taken,’ said David.

Acting on a tip-off that the negatives had turned up for sale, our undercover reporter contacted Geoffrey Giuliano, 62, a US author in Thailand who is known to have a vast collection of Beatles memorabilia.

Giuliano put our undercover reporter in contact with a mysterious seller named Carl Dahl, who Giuliano claimed to have worked with ‘dozens of times’.

‘Carl’ indicated that he would send Giuliano $500 for setting up the deal.

After almost a week of exchanges, an email containing two proof sheets showing negatives from the wedding were sent from Giuliano’s email address.

Claiming he didn’t have a bank account, ‘Carl’ issued instructions for our undercover reporter to transfer money via Western Union to his ‘senior partner and accountant Daniel’.

Giuliano said he had been instructed to sell the negatives on behalf of a friend but the deal soured when Giuliano suspected the reporter was acting for Ono and refused to sell them before launching into a vile tirade against her.