BETWEEN 1982 and 1985, BR’s Southern Region took delivery of 137 four-car Class 455s, which enabled the withdrawal of older slam-door stock, as well as the transfer of the Class 508 fleet, which had been introduced as a stop-gap in 1980, to Merseyside.
Within a few years, it became obvious to Network SouthEast, which had come into existence in 1986, that some two-car sets were also needed, to enable six-car services to be operated where they were too busy for a single four-car unit, but did not warrant the use of a pair of ‘455s’.
In September 1989, an order was placed for 24 two-car
