Brexit has put up to 25,000 British seasonal jobs in ski resorts and summer activity holidays at risk, with businesses saying they are facing an “existential crisis” because they will not be able to hire British staff after March if the UK crashes out of the EU.

A British entrepreneur has told how he has sold his two largest venues, Jack’s Bar and the Evolution restaurant in the French Alps resort of Meribel, because of fears over a cliff-edge Brexit. They were prominent spots on the apres-ski social scene with a combined turnover of £1.5m a year.

But Brexit has broken their business model, said former owner Charles Owen, managing director of European Pubs Ltd.

Ski package holidays, that typically include airport transfers, accommodation and lift passes, are traditionally staffed by British nationals who do everything from meeting and greeting to the chalet catering and cleaning.

Charles Owen, managing director of European Pubs Limited. Photograph: Charles Owen, managing director of European Pubs Limited

Owen’s business model is based on the availability of young British English-speaking staff to work for six months a season.

Under the EU “posted worker” directive, the travel industry can hire workers on a temporary basis but pay their taxes at home.

It the UK crashes out of the EU, the posted worker directive falls away and Owen did not want to take the risk that his workers would be illegal on 30 March 2019.

“There are 25,000 British people that are employed in the seasonal travel business, earning their salaries through the British system and paying tax in Britain.

“The mountains aren’t going anywhere, it’s just the staff in the bars and chalets and hotels won’t be British anymore. It is also a huge loss of British jobs,” he said.

“I have got together with 10 other CEOs in this business and it is a disaster. This is a common story now that people are selling up in the seasonal travel business.”

Owen said he blamed “out-of-touch” Conservative party politicians who have no idea of the challenges businesses are facing while they continue their civil war over Brexit.

“This sector generates more than £16bn towards British GDP and generates around £1bn revenue for HMRC, and yet we are in an existential crisis because of Brexit,” said Owen.

His story has been echoed by Diane Palumbo at Ski World, the UK’s largest independent ski specialist holiday company.

The firm employs 350 young Britons a year in what Palumbo describes as an “accelerated learning programme” for school leavers or graduates who want a career in business.

But Ski World fears after March this may no longer be possible.

“It’s a practical business finishing school. I had it 35 years ago and I’m gutted that the opportunities for the next generation of 18-24 years olds are being diminished because of Brexit,” said Palumbo.

“I am not sleeping at the moment because of the worry. The CBI said that a no deal would be a sledgehammer to British business, but to us that’s an understatement. It would be a complete catastrophe,” she added.

A consequence of a “Brexodus” of British staff from Alpine resorts is that the prices of holidays will go up, according to the Seasonal Business in Travel lobby group founded by Palumbo and Owen.

A recent survey found that enforced changes from leaving the EU will lead to a 31% increase in the cost of the British package holiday, whether skiing or summer camping.

“British people in 2016 did not vote to make their holidays more expensive or to limit the opportunities for their children or grandchildren,” said Owen.

“This is also going to reverse the democratisation over the last 35 years,” said Palumbo. “To have a chalet host cooking and cleaning for you, used to be preserve of the rich but as skiing has grown in scale, it has become something available to many more people. There is just not the local labour to do this.”

Even if there was an alternative workforce available in the Alps, what customers want are the “British people who meet you at the airport, organise your coach to the resort, your ski passes, and are there if there is an emergency”, added Palumbo.

If you work in or run an SME affected by Brexit, contact lisa.ocarroll@theguardian.com