The Windrush generation has been much in the news – and rightly so – since the scandal of the threatened and actual deportation of hundreds of them by the Home Office came to light last year. Numerous poignant and moving photographs of the original pioneers have been published, too, but few have packed the punch of Howard Grey’s extraordinary, historic shots taken at Waterloo Station 57 years ago. It would be hard to find pictures more emblematic of the Windrush era than these, yet for over five decades they remained not only unseen but unprinted, tucked away in a drawer in the photographer’s studio.

It was early in 1962 when word spread in the Caribbean that the British were about to change the laws on immigration making it much more difficult for West Indians to come here to live and work. The news created a panic in the soon-to-be-former colonies and there was a surge of people hurrying to the UK before the Commonwealth Immigrants Act of that year was passed.

When Grey heard reports one overcast, drizzly midweek day in May that passengers from apparently the last ship of West Indians were arriving on the boat train from Southampton to Waterloo, the 20-year-old assistant photographer grabbed two cameras and headed straight to the station. Now 77, Grey has the energy of a much younger man, his eyes lambent and mischievous as we look through his archives together at his house in Clapham, south London. He recalls the great throng of West Indians, perhaps three or four hundred friends and relatives, waiting at Waterloo with heightened excitement for the train to come in. The arrivals have clearly ignored the advice of the BBC booklet of the time, Going to Britain? – which warns the West Indians: “Do not put on your best clothes for landing” – and are dressed to a point beyond distinction. All the images are vivid, dignified and tender, the people they capture full of hope and anxiety. The pictures reveal a degree of maturity unexpected from such a young photographer.

Facebook Twitter Pinterest ‘The expectancy here is incredible. There’s so much going on. I was determined to get this whole sleepy row of women in. This is before the train arrives. They look apprehensive. There’s ambivalence there.’

Grey, who picked up his first Leica as a child, cut his photographic teeth as a 12-year-old in his father’s walk-in photographic shop in 1950s Isle of Man where holiday-makers posed for snapshots in a mock-up bar. He’s a third-generation photographer, from a Jewish family who fled the pogroms in Russia and Ukraine on an onion boat and ended up in England via Tilbury.

Looking back now, Grey believes he had an affinity with the West Indians because of his own family history. “The West Indians’ arrival conjured for me the last boat out of Odessa for my grandparents, not as dramatic as that, of course. But I said to myself, ‘Let me go and get a bit of the reality of this’,” Grey says.

Facebook Twitter Pinterest ‘Lovely to see her in the flowering of her pregnancy. There’s apprehension here; the stillness is palpable. The clothing is very much bespoke. There was nothing pret-a-porter about any of them.’

The sky was bleak as he caught a bus from his bedsit in Baker Street and arrived at Waterloo with his cameras, a Rolleicord (with a superb Rollei lens) and a Nikomat. “About 150 people came off the boat train. Whole families were there to greet them, dressed in their Sunday best.” Grey was thrilled that no other photographers had bothered to show up but his excitement was tempered by the weather and poor light. “It was one of those gloomy days, and the station was very dark. Its glass roof was still yellow from the grease and smoke screens of the second world war; then you had the black asphalt on the platform, and of course the West Indians had dark skin.”

Grey hated flash photography so was reluctant to use a flash gun. “I had an exposure meter reading that was dire and I knew I was in trouble.” He shot quickly and instinctively, going through three rolls of film in 20 minutes. “There wasn’t much forethought. I wasn’t framing a narrative. I just took pictures believing every one was a possible jewel.” Traipsing home in the rain, Grey was pessimistic, and in the darkroom his fears were realised. “Even when I pushed it, doubling the development time to work on the shadow areas of the negative, there was nothing printable there.”

He put away the negatives in a manila envelope and over subsequent decades went on to forge a successful career as an advertising photographer. Occasionally he’d reflect on the undeveloped West Indian photos but was ultimately phlegmatic. “I’d seen their potential and had taken the pictures but it had failed. There was nothing I could do. It was just a pity.”

More than 50 years passed and then one day in 2014 with the advent of digital cameras and scanners, Grey watched a TV programme about how new technology had revealed layers of text hidden beneath the surface of an ancient manuscript on vellum. He recalled one of his father’s sayings: “The detail is always there, even if you can’t see it at first.” He dug out the Waterloo negatives, and put them under high-definition scanners, “one scan for the shadows, one for the highlights and another for the mid tones. And then I brought them together, layered over each other; and up they came, the images I’d never seen! I was freaked. I couldn’t believe it. I saw the human drama of 1962 right there. I was revisiting the past and was absolutely astounded. I didn’t run around shouting “Eureka” down Clapham High Street but as good as… It was alchemy. It was just magic.”

Grey’s photographs are now housed at the Autograph gallery in east London and can be seen online at the gallery’s website. They were shown at the Black Cultural Archives in Brixton last year to mark the 70th anniversary of the first Windrush migrants and an untitled shot of a new arrival can be seen on the cover of my new book of interviews with the Windrush generation.

Facebook Twitter Pinterest ‘This was a Pathé news crew capturing the very moment of arrival. They’d have used three lenses; no zoom lenses in those days. I was pleased to have a scoop, or so I thought, as there were no other photographers. Again there’s so much going on here; it could be a still from a feature film.’

Grey has always been curious about the identity of his subjects but didn’t think to get their personal details when he shot them. He hopes maybe they’ll see their younger selves if they look now at the photographs. In a sense, through discovering the images he’s found his younger self, too. “The Waterloo West Indian experience was my first photoshoot after photographic school. Only 50 years later do I know what I achieved; and only in retrospect do I know what I was there for. It’s a moment preserved; these stories emerged and all of them are true.”

• Homecoming: Voices of the Windrush Generation by Colin Grant is published by Jonathan Cape (£20). To order it for £17.60 go to guardianbookshop.com or call 020-3176 3837. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99

• The Autograph archive is at Rivington Place, London EC2 and online at autographabp-iadl.co.uk