THE prestigious Caledonian Sleeper train is in danger of going to the dogs, a rail union warned yesterday after the notorious privateer set to take it over plunged into loss.

Contractor Serco — which soaks up wads of taxpayers’ cash in lucrative contracts across the public sector — panicked its investors earlier this week as its share value tumbled.

Newly released figures show it plunged from profits of over £100 million to a £7.3 million loss in the first half this year.