The British Rail Class 310 was a slam-door, alternating current (AC) electric multiple-unit passenger train (EMU) introduced in 1965 as part of the West Coast Main Line electrification project.

They introduced some new features; the first standard multiple units with disc brakes (emergency stop from top speed in 33 seconds over 800 yd (730 m)); the first naturally air-cooled rectifiers (silicon diodes on cups of beryllium oxide), inductors and transformers.

Initially they were primarily used on local services from London Euston to Bletchley, Milton Keynes, Northampton and Birmingham New Street, and within the West Midlands.

During the mid-1980s they underwent their heavy C1 refurbishment at Wolverton which included new flat windscreens, a corridor connection between the Motor Vehicle (MBS) and trailer (TSO), and a PA system among other modifications.

[clarification needed] When first arriving on the LT&S the Class 310 were modified with an additional plug being inserted in the dummy cylinder of each vehicle and a different size "choke" fitted in the Electro-pneumatic (EP)valve to improve the braking performance to that required on a more intensive service.

[citation needed] Also the cast BR double arrows were removed from the cab sides on arrival, or soon after at East Ham Depot.