The admission came during an Abta Brexit breakfast briefing on Tuesday – a day after the UK and EU agreed terms for a Brexit transition period, despite big questions remaining over the Northern Ireland border.

Andrew Stewart, chief financial officer at Hotelplan UK, parent company of Inghams and SkiTotal, said: “There is a difference between overarching policy and what’s happening at the grassroots.

“We’re feeling the effects of Brexit right now – when you send stuff overseas you’re also obliged to comply with local labour laws… and they can make your life very difficult at a local level. In the space of the last two months we have experienced more employment inspections than in the last five years put together… The immediate effects that we’re feeling are very hostile.”

It came as Abta chief executive Mark Tanzer demanded “candour and transparency” from ministers, as he accused politicians “on both sides of the Channel and the Irish Sea” as having been “long on rhetoric and short on detail”.

“It is time now… that citizens and businesses can start to plan for their future,” he said.

Tanzer’s comments were echoed by Stuart Leven, vice-president of Europe, Middle East and Africa, and managing director of Royal Caribbean Cruises Ltd, who told delegates: “It’s time to do some contingency planning.”

“We don’t know what’s coming, but as with any organisation we have to accept our guests may not have the freedom [to travel] like they do today, and we may have some challenges with our staff moving around,” he said.

Kate Nicholls, chief executive of UKHospitality, said the challenge was that “there are too many scenarios to plan for”.

“At one end you have no deal, and I don’t think there is any likelihood of a no deal, but the permutations of that and what we might end up with are just too many to plan for,” she said.

Despite this, Nicholls insisted she remained “cautiously optimistic”: “We shouldn’t underestimate the good news we had yesterday [regarding the transition deal].”

Leven added: “People will still go on holiday after March 29 next year.”