The vehicles will be formed into four sets of 16 coaches with 11 spare vehicles.

Caledonian Sleepers will offer various types of accommodation including en-suite berths, standard berths, standard seats, and pod flatbeds. Each rake will also include a brasserie-style Club Car.

The order is being financed by Caledonian Sleepers Rail Leasing, a subsidiary of Lombard North Central, which is part of the Royal Bank of Scotland Group, with the aid of a £60m grant from the Scottish government.

Serco was awarded a 15-year contract by Transport Scotland last May to operate the Caledonian Sleeper franchise from April this year. The new CAF coaches will enter service in April 2018.