Shortly after taking over operations, the company initiated a series of projects to improve service levels, including the procurement of new trains and the launch of the Norwich in 90 programme to reduce travel times between several major locations on its network.

In December 2024 it was announced that Greater Anglia, would be one of the first train operating companies to be brought into public ownership as part of the government’s re-nationalisation plan, following South Western Railway and c2c.

[3] In December 2003, the Strategic Rail Authority awarded the Greater Anglia franchise to National Express, which began operations on 1 April 2004, initially under the brand-name One.

[6][7] Following a change of government as a result of the 2010 general election, the DfT announced in June 2010 that all refranchising would be put on hold while a process review was conducted.

[15] Prior to Greater Anglia, the last period of substantial investment in the region had been nearly 30 years earlier, specifically the electrification of the line north of Ipswich.

During the negotiations for the award of the franchise, Greater Anglia pledged to undertake numerous investments that would improve the various services and facilities offered.

Abellio had acknowledged such calls in 2012, but could not justify making very substantial investments during the initial franchise period due to the short timescale involved.

[16] There has also been an aspiration to increase the number of trains between Norwich and London to three per hour, although capacity constraints such as the single-track section in the vicinity of the Trowse Swing Bridge would need to be overcome to facilitate this.

One commitment of the new franchise period is the purchase of 1,043 new carriages, 660 from Bombardier Transportation's Derby Litchurch Lane Works with the remainder being built by Stadler Rail.

[24] Reportedly, Greater Anglia has incorporated numerous planning and operational practices of the Japanese railways, such as the use of digital twin simulation software for analysing performance and developing its timetables, since the acquisition.

[26] In February 2023, Transport UK Group concluded a management buyout of Abellio's United Kingdom business, which included its share in Greater Anglia.

The National Union of Rail, Maritime and Transport Workers (RMT) has accused Greater Anglia of conducting alleged strike-breaking tactics and claimed that its use of stand-in conductors led to passengers' safety being jeopardised.

[36] In the lead up to the 2024 United Kingdom general election, the Labour Party of Keir Starmer committed itself to bring the passenger operations of the British rail network back under state ownership.

[41][42][43] A number of improvements were planned during the first franchise period (2012–2016) which included:[11] The following improvements have been planned as part of the Abellio bid for the East Anglia franchise (2016–2025):[44] As of June 2024[update], the following services operate during the off-peak period, Monday to Friday:[47] Greater Anglia operates the Stansted Express sub-branded airport rail link between Stansted Airport and London Liverpool Street.

[48] As of June 2024[update], Stansted Express' off-peak services Monday to Friday are:[47] Punctuality statistics released by Network Rail for service report period 7 of 2013–2014 (15 September – 13 October 2013) were 94.0% PPM (Public Performance Measure), down 1.0 percentage point on the same period ine the previous year, and the MAA (Moving Annual Average) up to 12 October 2013 also fell slightly to 92.3%.

[54] There were also concerns with the 'sewage mist' from passing trains making Network Rail staff ill; Greater Anglia announced it was "working closely" with the government to introduce a fleet upgrade.

[65] In March 2020, testing of the new Class 720 fleet finally began and continued despite the ongoing COVID-19 pandemic, in order to allow the first unit to enter service within the next few months.

[68][69] Class 360s began moving to Kings Heath TMD in Northampton in June 2020 for modifications by Siemens to make them capable of 110 mph speeds, in preparation for their transfer to East Midlands Railway (EMR).