Previously unseen images of The Beatles give us a rare insight into the band in their inner sanctum at Abbey Road. Ahead of their forthcoming appearance at Norwich’s St Giles Street Gallery, Keiron Pim found out more from photographer Frank Herrmann and gallery owner David Koppel.

If these photographs depicted any other four young men in their workplace, sitting around looking bored and having their lunch, it is unlikely there would be much interest.

But Frank Herrmann's long-lost images are of The Beatles, and so all rational standards tend to go out of the window. Such is the degree of fascination with the band 37 years after its demise that the thought of hitherto-unseen pictures of them drinking tea and smoking cigarettes is enough to have fans salivating with anticipation. Throw in the fact that Herrmann caught them at Abbey Road during the recording of Sgt Pepper's Lonely Hearts Club Band (released 40 years ago yesterday, in case you hadn't heard), and that it was only a few hours before the photoshoot for Sir Peter Blake's iconic album cover, and you have what is the band seen charmingly off-guard at a critical moment in its history.

“It is only with hindsight that I discovered that Abbey Road was their private sanctuary, and I was entering the holiest of holies - normally no one was allowed to take pictures inside,” says Herrmann, who took the photographs on March 30, 1967, for The Sunday Times. Now aged 74, he is largely retired and splits his time between London and a weekend retreat near Diss.

“We were asked to do a piece on the mechanics of the recording. We were given one hour during the lunch break, so we saw them having a cup of tea, sitting having their lunch. I didn't hear the music, they were all plugged in. Paul McCartney was playing guitar; Ringo wasn't doing much. John Lennon said 'how are you doing?' - he was the friendliest of them.

“They didn't want anyone who would say 'Can you stand over there, John?'. It was to be a fly-on-the-wall occasion, which was my favourite way of working, being able to observe people discreetly.”

The band was right up against deadline for completing Sgt Pepper. Sir George Martin was adding harpsichord to With a Little Help from My Friends while Herrmann was there. Herrmann was chosen because he was known for his unobtrusive and efficient manner. The band's manager, Brian Epstein, apparently felt that some candid shots of The Beatles at work would help win them even more fans. But only one or two of the pictures were used to accompany the article, and the two rolls of film that Herrmann shot stayed in the Sunday Times' archive until he left the paper in 1987.

“I was allowed to take a set of negatives with me when I left, so I took my favourite Beatles pictures with me, took the negs out, contacted them [ie transferred them to a contact sheet] and gave back the rest,” he says.

When in 2002 he was asked to contribute photographs to illustrate George Martin's autobiography, he went to collect the remaining negatives only to find that they had disappeared. All that remained of those pictures was the tiny images on the contact sheets - and it is only now, thanks to recent advances in technology, that they can be turned into the quality prints that will be hanging on the walls of St Giles Street Gallery from today, 20 of which have never been seen before. If it wasn't for gallery owner David Koppel being such a fan of the band, his old friend's unseen Beatles photographs probably still wouldn't be known to the public.

“It was Christmas and I asked Frank if I could see his Beatles contact sheets,” says Koppel. He took a look at them and for Koppel, himself an acclaimed photographer who made his name as a Fleet Street paparazzo in the 1980s, it was akin to striking gold. But there was a hurdle to overcome first.

“The reason this show has come about is digital technology,” he explains. “I said 'What's to stop us scanning these contacts?' Frank did a little experiment and thought they were awful and put off the idea. I said 'let me take a look at them…'”

Koppel tried again using higher resolution scanning technology and, in his words, he “printed one off, framed it, gave it to Frank as a gift and he thought it had come from a negative”.

As Herrmann says: “If you tried that before digital photography you would have lost an enormous amount of detail. But with digital, amazingly enough, you can do it.”

The latest technology was not only used to salvage the images. Just as the Beatles' music has been polished and remixed in recent years using modern remastering techniques, so some of Herrmann's pictures have taken on a new life with a little digital enhancement. These images, drawn from the forthcoming book Summer of Love by Sir George Martin (see panel), have had various alterations: whether through being stylised and tinted monochrome blue, or reproduced against a floral background, the pictures have been lent a psychedelic hue befitting the spirit of the era in which they were taken.

The exhibition has been six months in the making - Koppel jokes that he'll be glad not to see any more Beatles photographs until the 50th anniversary of Sgt Pepper - and to add the finishing touches he has been compiling items of Beatles memorabilia to decorate the gallery. For instance, visitors will enter the gallery to be greeted by a vivid Yellow Submarine welcome mat.

The gallery, which has been in business for five years, will be selling the limited edition prints for prices ranging from £400 to about £1,500 for the large, remastered colour images. Each of the black and white photographs will be available in three sizes: 10in by 8in (a limited edition of one per image), 16in by 12in, and 20in by 16in, with both sizes each in a limited edition of 25 per image. So far Koppel's gallery has taken calls from Beatles enthusiasts in Australia, Amsterdam, Belgium, America and Israel. The large colour-enhanced photos make up the remainder of the exhibition.

“We thought wouldn't it be great to fill the rest of the gallery with remastered photos,” says Koppel. “We have put them on canvas, which looks amazing.”

Herrmann was born in Berlin in 1933 though his family moved to London in September of that year. He is well accustomed to photographing celebrities: others in his portfolio include Orson Welles, Sean Connery, John Gielgud, Winston Churchill, Duke Ellington, Jackie Kennedy, Harold Macmillan and Ronald Reagan. His work spans from the Yom Kippur War and the 1968 Paris riots through to sporting occasions such as the John McEnroe v Bjorn Borg at Wimbledon.

For him, the Beatles photoshoot was less than an hour's work in a varied and acclaimed career that has seen him labelled one of the great photojournalists of the latter part of the 20th century.

For fans of The Beatles, however, that short spell in Abbey Road captured a rare glimpse behind the scenes of the most famous band in the world at the peak of their powers. Herrmann's photos form an irresistible document of the time.

t The Unseen Beatles exhibition by Frank Herrmann runs at the St Giles Street Gallery, 51 St Giles, Norwich, from today, June 1, until September 1. For more information telephone the gallery on 01603 663333, e-mail info@sgsgallery.com or log on to www.sgsgallery.com