FOREIGN tourists travelling on the Caledonian Sleeper were left without berths after turning up to discover they were booked on coaches that did not exist.

The fiasco, which happened on Tuesday night, comes less than a week after Serco took over the franchise with a promise to transform the Sleeper into a "a tourist rail experience to rival the best in the world".

Some 20 passengers, including a party of Canadian teenagers and an Australian couple, turned up at Edinburgh Waverley station to catch the overnight Sleeper to London, but had to wait on the platform when it emerged that their reservations were for carriages which were not there.

The bookings had been made on April 1, the day that Serco took over the franchise.

It is understood that the problem was caused by a glitch with the national booking system, and that all carriages which were supposed to be at Waverley were there.

Departure was delayed while train staff hurried to find vacant berths available on the Glasgow-London Sleeper instead. Affected passengers were eventually dropped off at Carstairs station in the early hours of Wednesday morning, where they transferred onto the alternative train.

Rob Bruce, a businessman and regular Sleeper commuter who was travelling on the service, said it was "a real shambles".

He said: "When I arrived at Edinburgh Waverley station on Tuesday night to catch the sleeper to London there were lots of people standing around on the platform and I thought that was a bit odd because normally people get straight onto the train and get into their compartments.

"I went into the bar on the train and the attendant was phoning headquarters. It seemed there were people booked onto coaches N and P and those coaches didn't exist. There were N and P coaches on the Glasgow train but they were full.

"Serco took over the booking of the sleeper on April 1 and it was their mix up.

"There was a party of Canadian teenagers who were affected and their tour guide was stressed. They had a busy schedule and it would all be messed up if they didn't get to London.

"In the end, they all filed onto the train and were standing in the corridors and the bars. There was an Australian couple affected too. They were saying how chaotic it was. Everyone was pretty dismayed and stressed. The staff were saying this had never happened before."

Mr Bruce added that the on-board crew had been "fantastic" in handling the crisis.

Serco, who also run Australia's transcontinental India Pacific service linking Sydney and Perth, took over the Sleeper franchise on a 15-year term.

It was previously operated under the ScotRail umbrella.

They have committed to revamp the service with £150 million of new rolling stock by 2018.

There will also be a brasserie-style club car, improved catering showcasing the "best of Scottish food and drink", the option to stream films and television via free wifi, and new aeroplane-style sleep kits including scented pillow sprays and eye-masks.

Ryan Flaherty, guest services director at Caledonian Sleeper, said: "I'm really sorry that these people had a problem with their booking - it shouldn't have happened.

"We have identified the problem and we are confident that it will not happen again."