Class 80[1] was the TOPS classification allocated by British Rail to the prototype 25 kV AC electric locomotive.

British Rail allocated the number E1000 (and later E2001)[2] to the locomotive following its conversion from gas turbine propulsion.

In addition, it was also converted from Co-Co to A1A-A1A wheel arrangement when the centre traction motor from each bogie was removed.

Once the locomotive had been stripped, the new electrical equipment was installed which included the transformer, the Stone-Faiveley pantograph (for which a section of the roof had to be lowered), a Brown Boveri air blast circuit breaker and the Hackbridge-Hewittic mercury arc rectifier units.

[citation needed] Once the production locomotives (Class 81 onwards) were in service, E2001 was no longer required.