To replace their ageing electric locomotives of classes 81 to 85 from the early sixties, British Railways ordered a new mixed traffic locomotive in the eighties. The design ultimately selected for production was a four-axle development of the class 87, while the competing six-axle class 89 didn't make it out of the prototype stage. After initial plans to call the new locomotive class 87/2, it was given a the new class number 90 due to the numerous changes compared to the class 87.

The most noticeable difference was the bodyshell that had a completely new design. At 5,000 hp, the power level was the same as in the class 87 and also the traction motors were of basically the same design. But power control was now electronically via Thyristor. A time-division multiplexing system was added to enable double heading and the use of driving trailers. Due to some teething problems, they were nicknamed “Skodas” in reference to similar problems encountered with cars of the Czechoslovak brand being imported to the UK at the same time.

50 locomotives were produced between 1987 and 1990. When BR was sectorised in 1991, half of them were assigned to passenger services and half to freight services. The freight variant was re-geared from 110 mph (177 km/h) to 75 mph (121 km/h), lost its electric train supply equipment and was designated class 90/1.

After privatisation, EWS alone inherited 25 locomotives of both variants. Passenger services were also provided by other private operators like Virgin Trains. When passenger services with the class 90 ended around 2020, a total of 24 locomotives each was now owned by EWS (now DB Cargo UK) and Freightliner. The remaining two were owned by Locomotive Services Limited. DB Cargo UK either stored or scrapped all its locomotives in 2023 due to high energy costs and replaced them with diesel locomotives.