In the age of swinging optimism – jet travel, space exploration and a sense that technology could compress distance – the new-fangled hovercraft was a sea-born adventure waiting to unfold. It looked, to the public, like a machine from a paperback science-fiction future:a great skirted hull humming on a cushion of air, lifting cars and people above chop and foam and delivering the Channel crossing in a blur. And for a time, from the late 1960s through to the 1980s and beyond, those machines did exactly that: they flew, in the way that only something that sits half-in, half-out of two worlds can fly.

Like all good stories of invention, this one starts in a small workshop. Christopher Cockerell, an engineer who had worked on radar, conceived the idea that you could raise a vehicle on a curtain of moving air, minimise hull drag and – perhaps – make the sea less of an obstacle to speed. The SR.N1 prototype proved the physics: it crossed from Calais to Dover on 25 July 1959 and, as The Guardian later recorded, “the SR.N1 was capable of 30mph, at a height of 15 inches.” It was a modest performance on paper, but the symbolism was powerful.

However, the jump from prototype to commercial application was ambitious. British industry and operators dreamed big: build not just a novelty ferry but a car-carrying, high-frequency service that could make continental travel and motoring effortless. The SR.N4 – the so-called Mountbatten class – was the result. A leviathan by hovercraft standards, built to carry hundreds of passengers and dozens of cars, with Rolls-Royce marine turbines giving the sensation of being on a very loud, very powerful flying carpet. The SR.N4’s scale and the newer stretched Mk II and MkIII forms gave operators a credible product: a true vehicle ferry that was also a spectacle.

Optimism ran high. Cockerell himself envisaged even more daring projects. In contemporary reports, he spoke of possibilities such as a hovertrain that might someday cut the journey between the centres of London and Paris to an hour – a comment that captures both the engineering hubris and the public hunger for new modes of high-speed travel.

If the hovercraft’s technical heart was daring, its public soul was pure theatre. Picture a Dover or Ramsgate hoverport on a summer morning: crowds gathering, cameras clicking and film being wound on, the great skirts at the water’s edge rippling as the craft lifted and surged. People loved them for the pure visceral thrill. As one museum trustee put it decades later, “You still get a crowd watching it at each end. The great thing about the hovercraft is its amphibious nature. It can go anywhere… up a sandbank, over a coral reef.” That capacity to transcend port infrastructure, to shrug off piers and tidal constraints, was part of the romance.

I vividly remember trips across the Channel using the Hoverspeed service, one of the later operators of Britain’s cross-channel passenger hovercraft. As a child, it was impossibly exciting to watch spellbound as this vast four-prop heifer approached the shoreline and then settled on the concrete slipway, its rubber curtain deflating to allow the plane – which is what it was – to almost curtsy to waiting drivers and foot passengers.

The car ramp's nose would lower, 50-odd cars would emerge and then it was your turn to drive on. The only thing that would have been more exciting was strolling up the gangway of the Millennium Falcon.

It was quick to unload and load, and was snug in the passenger seating area, where out of the 360 seats those by the windows were most prized, assuming the spray wasn’t too severe. The noise as a set of 12-ft diameter fans fed air into the airbags to lift the hovercraft, and those Rolls-Royce engines restarted, was far from relaxing. Vibrations fizzed through every part of the craft.

And then it was off, a quick turn-round performed on the concrete slipway, and a wave as you passed other Hoverspeed craft. Captain Nick Rose said the record for a Dover to Calais crossing was around 22 minutes, not bad for a craft that weighed about 330 tons when laden. But pick a rough day and you really felt the impact as the nose of the hovercraft slammed against the waves.

The downfall of the passenger hovercraft

Its inherent complexity brought about uncomfortable realities. Hovercraft were expensive beasts to keep in the air – they guzzled fuel, were mechanically complex and required bespoke maintenance. Their skirts were consumables: rubber that had to be repaired or replaced over time. When global fuel prices rocketed through the 1970s, the economics bit hard. The simple truth was that moving a passenger across the Channel by hovercraft cost far more than doing so on significantly more spacious ferries.

Commercial pressures multiplied. Two rival hover operators – Hoverlloyd (Ramsgate–Calais) and Seaspeed (Dover–Calais) – pushed capacity and schedules through the 1970s, but they also struggled with the basics of running a regular maritime service with a fleet of technically idiosyncratic craft. The companies merged in 1981 to form Hoverspeed, but consolidation did not cure the underlying costs. Meanwhile, their competition was not standing still. Conventional roll-on/roll-off ferries grew larger, loading got faster and their operators pushed comfort and relaxation (bars, restaurants, shops and sun decks) rather than shorter journey times.

High-speed catamarans improved efficiencies in a way hovercraft could not match. The picture was further darkened by regulatory and commercial changes: tougher environmental and noise regulations, and more stringent rules around duty free sales shaved away at revenue and operating flexibility.

The craft themselves embodied contradictions. On good days they wallowed over flat seas like racing gulls; on bad days they rattled and sprayed, crews and passengers feeling every windshift. They required specialised terminals and lots of hands to keep the clockwork running. The very design features that made them exciting – the open decks, the audible turbines, the skirted hull skimming the sea – also made them tiring and occasionally alarming once the novelty-factor had worn off.

There were bravura moments. The Princess Anne and her sisters achieved crossings that felt miraculous: on her best showing the Princess Anne recorded Dover–Calais times that shortened holiday 'sailings' to a coffee break. But the public’s appetite for spectacle was finite and the commercial realities facing operators were impossible to escape.

And, then, in 1994, the final nail in the coffin proved to be the opening of the Channel Tunnel.

Over time business for hovercraft operators declined. Hoverspeed’s services slowed and then stopped; on 1 October 2000 the last SR.N4s – the Princess Anne and Princess Margaret – made their final scheduled Channel runs and the great era of car-carrying cross-Channel hovercraft ended, with hundreds of well-wishers turning out to mark the occasion

What looked for decades like the transportof tomorrow had, in practice, been a brilliant but expensive detour in the history of cross-Channel travel.

You can still experience it to this day. Thankfully, a small, stubborn line remains: Hovertravel’s passenger-only services across the Solent – Southsea to Ryde –have run since 1965 and continue to flourish because the route’s geometry and demand suits the craft. And one SR.N4, the Princess Anne, survives inpreservation at the Hovercraft Museum at Lee-on-Solent, an artifact and anargument.

The hovercraft left a mixed legacy. It was a major engineering achievement, a highlight of engineering innovation and a cultural artifact that inspired future ideas. But it also taught a blunt lesson about the economics of transport: speed and novelty are not enough unless they can be married to operating costs, maintainability and resilience in the face of evolving regulations.

Christopher Cockerell’s invention could not be uninvented – “there’ll always be hovercraft,” fans of the concept can say with pride – but the number of travellers prepared to pay to keep them at scale proved smaller than the dream of one engineering maverick.