When the operators of the most popular steam train service in Britain decided to challenge the safety authorities, they were confident that sentiment and nostalgia would win out. They’ve been proved wrong. The health and safety brigade has triumphed and consequently the Jacobite train, popularised in a Harry Potter film and running along one of the nation’s most attractive rail lines between Fort William and Mallaig on the West Coast, will no longer operate.

It’s the culmination of a lengthy battle between the train-spotters and the grey men of the Office of Road and Rail (ORR), who are insistent that a temporary concession to allow the trains to operate without key safety equipment cannot be extended. That key safety issue is that these carriages, which date from the early days of British Railways, do not have a central door-locking device that is now mandatory on all trains operating on main lines but are still allowed on heritage routes on which services are limited to 25 mph.

The operator, West Coast Railways (not to be confused with Avanti West Coast), was given a temporary dispensation to operate these old carriages more than a decade ago but its failure to introduce the central-locking device now means a permanent ban.

Is this ’elf and safety gone mad? After all, trains traditionally ran without any such safety device and slam-door trains operated until the middle of the first decade of this century. West Coast Railways argues that fitting the device would make its operation uneconomic. Indeed, one could ask how likely it is that people will risk their lives by opening doors while a train trundles along in the spectacular scenery of the west Highlands? This is not India, where passengers regularly sit in open doorways watching the world go by (I have done so myself, without coming to any harm). Train fans do not generally allow their enthusiasm to get the better of them by jumping on the tracks in front of trains to take pictures or lean their head out of windows with fatal results.

But while West Coast Railways is presenting this as a freedom issue, with it standing up for the rights of train enthusiasts against faceless bureaucrats obsessed with the tiniest risk, even a shallow dig into the background of this story suggests there is an understandable caution. In the 1980s, there was a spate of deaths on High Speed 125 trains as doors mysteriously flew open mid-journey, and it was only after a lengthy newspaper campaign that central locking, which prevented such mishaps, was mandated.

Last year, West Coast Railways sought a judicial review into the ORR’s decision not to continue to allow the derogation from the rules. The reasons set out in the court’s unequivocal decision against the company are revealing. For a start, there has been plenty of time to sort this out and the judge pointed out that other heritage railway companies had fitted the equipment without a problem. The key issue, though, is money. West Coast Railways claims it would cost £7 million to fit its two trains with the equipment and that would make the service unviable. ORR, however, presented detailed evidence, accepted by the judge, which argued the bill would be far smaller, possibly as little as £700,000 for the two trains. Moreover, she argued, a £10 rise in the Jacobite fare would raise £1 million, easily covering the extra. And that does not sound too outlandish given that the return (West Coast Railways does not do singles) first class fare is already £98, with £65 for steerage, compared with an advance single on a conventional service costing as little as £8.20.

Should we be tempted to regard the safety risks on a few puffa trains as being nothing much to worry about, it should be noted that West Coast Railways has form on potential dangers of this sort. The company was involved in what, in my 30 years of writing about the railways, came close to becoming one of the worst disasters in British railway history. In March 2015, a steam tour, headed by a locomotive called Tangmere, passed a signal at danger after the driver had disconnected a safety device. Belatedly realising his error, he brought the train to a halt across a mainline junction at Wootton Bassett, where a high-speed train with 240 passengers aboard had passed just 45 seconds previously. Had it hit the steam locomotive, there is no doubt there would have been a very high death toll.

West Coast Railways was temporarily banned and fined £200,000, and the driver given a suspended jail sentence. West Coast has had numerous subsequent run-ins with the safety authorities which resulted in further temporary bans.

The company has requested a temporary derogation in the hope that this will be allowed while its longer-term application for a further ten years is considered. However, according to one senior industry source, this is not likely to succeed: ‘In the early days of privatisation, there was a bit of a Wild West feel to the railways, with people being very gung-ho in terms of the precautions they were taking. Now that has changed and that seems to have resulted in the hardening of ORR’s attitude towards such cases.’

With no mood for compromise from the safety regulator, West Coast Railways will have to comply or there will be no steam trains on the West Highland Railway this year. Not all hope is lost, though. Other operators may well come forward to provide what is clearly a popular and potentially lucrative service. For this year, though, Harry Potter fans will have to seek their pleasure elsewhere.