They were introduced to replace an ageing fleet of Mark 1 sleeper cars built to various designs and which dated from the late 1950s to early 1960s.

[3] As of October 2019[update], the only mainline operator of this type of carriages are Great Western Railway on the Night Riviera, whose fleet was refurbished in 2017.

Mk3 sleeper vehicles remain in use on the Great Western Railway's Night Riviera from London Paddington to Penzance in Cornwall.

All Night Riviera sleeper carriages have been refurbished, and feature keycard locks, new lighting, a wardrobe and under-bed storage.

Since 2016, a sleeper repatriated from Denmark has been operated as a static hostel for members of the public by the Telford Steam Railway.