Meanwhile, Mark Drakeford has described omicron as the “most serious development in the pandemic to date”.

In the week before Christmas, the Welsh First Minister announced a slew of new restrictions to come into force after December 26 including the closure of nightclubs, a two-metre rule on social distancing in public areas and no more than six people allowed in pubs, cinemas and restaurants.

Mr Marks said that Mr Drakeford’s “draconian” policies will inevitably encourage people to cross the border for New Year parties.

He said: “I fully expect people to cross the border. If you’re in south Wales, it will be into Bristol. If you are in north Wales, it will be into Chester and Liverpool. This has happened before.

“If I was an 18-year-old in Cardiff, I can imagine some of my friends might want to go into England and I don’t think we should be naive enough to think that isn’t going to be the case.

“If it was the other way around, it would also work. If the Welsh were more open with less restrictions, you can bet your bottom dollar it would flow the other way.”

Mr Marks added that more people are likely to travel from Wales into England rather than Scotland as it is only a 40-minute drive from Cardiff to Bristol, while Edinburgh to Newcastle clocks in at two-and-a-half hours by car.

Michael Kill, the chief executive of the Night Time Industries Association, added: “Without a doubt, I think people who live on the borders may well cross into cities that are close to Wales. There will be people who cross the border because they have already had pre-booked tickets to go to bigger events.”