The British Rail Class 379 Electrostar is an electric multiple unit (EMU) passenger train which was designed and built by Bombardier Transportation.

[2] While the type was largely intended to increase capacity, its introduction did enable the withdrawal of ageing units such as the Class 317 EMUs; the programme also involved various infrastructure improvements.

According to industry periodical RAIL, these lines had received considerably more infrastructure investment as well as new rolling stock that had enabled both non-stop services and a higher top speed of 100 mph (161 km/h), the WAML was largely worked by a two decade-old fleet of Class 317 electric multiple units (EMU) on infrastructure that restricted speeds to 80 mph (129 km/h) and only provided sufficient capacity for stopping services.

[2] Accordingly, an order valued at £155 million was placed with rolling stock manufacturer Bombardier Transportation for 30 EMUs, these were subsequently designated as the Class 379.

[2] The trains had been ordered as a part of the wider NXEA Service Improvement Plan, which was enacted to expand capacity on the heavily crowded lines into London Liverpool Street.

[2] The trains were manufactured at Bombardier Transportation Derby Litchurch Lane Works; the first unit was formally unveiled on 13 October 2010.

[15] To increase serviceability and support the maintenance process, the Class 379 has been fitted with Bombardier's Orbita predictive fault monitoring system.

On 17 March 2011, the first two units, 379005 and 379006, performed the type's first service with a high-profile launch by Secretary of State for Transport Philip Hammond.

[16] The type's introduction was relatively trouble-free, with only minor issues such as moving the onboard catering trollies without damaging the interior being quickly resolved.

[19][20] Due to high leasing costs Greater Anglia withdrew the Class 379 fleet from service in February 2022, after which the units were placed in storage.

[3] In March 2024, Porterbrook announced that they had purchased the units from Akiem, and that Govia Thameslink Railway planned to use the trains on Great Northern services.