A sleeper train takes 0 useful hours, because you’re asleep.

Plus you potentially save on a night’s accommodation.

Last time I took the Caledonian Sleeper was for a morning meeting in Glasgow. My colleagues flew from Luton on the first morning flight and turned up irritable and tired. I got the Cally Sleeper and was fresh as a daisy with no time wasted - in fact I could do a couple of hours’ work while they were trogging around airports and planes.