It was 50 years ago today: new remix only adds to Sgt Pepper’s magic

It is one of the greatest albums ever. And the remastering of Sgt Pepper’s Lonely Hearts Club Band by Giles Martin has only added to the magic.

Ringo Starr, John Lennon, George Harrison and Paul McCartney working on Sgt Pepper’s Lonely Hearts Club Band at Abbey Road Studios in London, 1967. Courtesy Apple Corps Ltd

An evening in early April. Outside Abbey Road Studios in north-west London, tourists are performing their customary dance with irate motorists as they attempt to have themselves photographed on the zebra crossing across which The Beatles walked in 1969 for the cover shot of Abbey Road.

Inside the complex, a group of 100 people are seated in Studio Two – another historic landmark, if one less easily accessible to the public. Here, guests are looking around, taking photos on their phones, peering up the stairs to the control room: spaces once populated by living, working, actual Beatles as they went about their business making some of the world’s greatest music.

It is 50 years ago today, pretty much, that the Beatles released their album Sgt Pepper's Lonely Hearts Club Band. The record starts with an orchestra warming up and ends with a thunderous piano chord. There are sentimental songs and otherworldly trips, rooster noises and laughter. It's the pinnacle of the band's achievement but possibly also marks the beginning of their end. Shortly after, John Lennon and Paul McCartney became creatively estranged. Here, though, they are still working genuinely in partnership and it's magnificent to hear.

As the producer’s son – a 40-something named Giles Martin – tells the gathering, it has been quite something to work on such an album. From the start of their recording career in 1962, his father George worked with the Beatles to turn their ever-expanding musical brief – feedback, sitar drones, a song which would sound like “monks chanting on a mountain top” – into something which might be technically achievable in a recording studio. From late in 1966 to April 1967, he embarked on their most ambitious project yet: a release on June 2, 1967 that was both nostalgic and thrillingly contemporary. On the original vinyl record, the tracks were all run together with no gaps between them, to create a seamless trip into the Beatles’ new world.

The group worked tirelessly on the album. They spent 30 hours recording the final song A Day in the Life – three times longer than they spent on their entire debut LP (Please Please Me) four years earlier. Long into the night, they laboured on the mono mixes of the original recordings, then retired to their homes with acetates of the night's work to continue listening. The stereo mixes, roomier affairs, were created by studio engineers, with Beatles seldom present. Before this one, the last major Beatles project was the mastering of the catalogue in mono for vinyl – reflecting the appetite for this form among the deepest listeners of the band.

The album has been reissued in four editions: a six-CD super deluxe; double vinyl set; double CD and single CD. As Giles Martin now illustrates for the room, the aim of this new 50th anniversary edition – his remix of the original album with a disc of unheard takes; a deluxe six-disc set in which 33 outtakes can be heard in order of their recording; the first time the vault has been opened in this way for a single Beatles album – is to combine the best of these two positions. Namely to preserve the impact and focus of the mono mixes, combined with the clarity and separation of the stereo. Paul McCartney told him not to be too reverential. He said something along the lines of it being a good idea to push the envelope now and then.

Sgt Pepper's Lonely Hearts Club Band was certainly a record to do that. At concerts the previous year, the Beatles were still playing Chuck Berry cover versions – their complex studio output not being something they could reproduce live. Now retired from touring, they became fictional performers: the album's music would be provided by a brass band, offering a programme of light entertainment, as might once have been heard near a bandstand in a provincial British park.

It's a delightful, innocent conceit – but the concept is a loose one. The title track opens the album, and introduces Billy Shears (in fact, Ringo) to sing With a Little Help from My Friends. The penultimate track (the final song recorded, April 1, 1967) is a more rocking reprise of the opener. All around these songs, however, is music which bears no relation to brass bands per se, but is about familiarity, change and looking at the world with unjaundiced eyes.

Penny Lane/Strawberry Fields Forever, the Beatles' single of February 1967 introduced the ideas which the album then went on to develop. As you can hear from demos included here, both songs made psychic pilgrimages back to sites known from childhood – McCartney to a busy thoroughfare; Lennon to the grounds of a children's home where an annual summer fête was held. Penny Lane is lovely, but Strawberry Fields Forever, with its melting tempos and multiple layers, is where the Pepper method reveals itself. Potentially, the album might have distanced the group from their audience – it was, after all, not every Beatles fan who could have, or even wanted to have, participated in the mind experiments which helped to bring the band to this new place. The Beatles would never again play live and were also plainly no longer the same disarming fellows who had appeared on Sunday Night at the London Palladium. One might begin to think them unreachable.

In fact, the Beatles took everyone along for the ride. Pepper wasn't only a place for paisley-shirted hipsters but was – as Being for the Benefit of Mr Kite! had it – a place where "a splendid time is guaranteed for all", young and old, children and parents.

Listening to the album again, you wonder at the subtle relationship between McCartney's She's Leaving Home (in which a teenager runs away while her parents are asleep) and When I'm Sixty-Four, which seems to depict those same parents at the start of their marriage, not looking for revelation, but forward to their dotage, when they will be comforted by their memories. In a time when generational order was being questioned, McCartney's compositions gently probe questions of age and experience, and the value of unreported working-class lives.

As much as a magical and multi-layered sound world, it's also a recognisable one. You could take Pepper psychedelically, or you could take it at face value. Who hasn't taken a walk back to their old school, as John Lennon does on Good Morning, Good Morning? Many a young person could empathise with trying to date someone who still lives with their parents (and sisters), as does Lovely Rita. It works either way.

Fixing a Hole is about just that: mending the roof to get the job done and to move on to more interesting things. The album's closer A Day in the Life surreally reports the death of an British aristocrat in freaky modal sound (Lennon's bit) – but also has ties to the everyday (McCartney's bit). The middle section, in which Paul daydreams on the bus going to work, could be anyone's experience.

The second disc of this anniversary edition, with its charming studio chat and demo takes, underlines this idea, bringing those original, empathetic Beatles right back. The Beatles were not fixated on the idea of making the greatest-ever album. They were, as Giles Martin puts it, making noise in a room, playfully trying things out. On the second disc, you can hear them do it. Sometimes they even get things wrong.

Pepper has always surprised and delighted its listeners, and this new expanded edition helps it to do so again. Namely to reveal how, even when their music was at its most unique and unassailable, the Beatles were actually not that different from anybody else.

John Robinson is associate editor of Uncut. He lives in London.