Trenitalia c2c Limited, trading as c2c, was a British train operating company that operated commuter services from the London terminus at Fenchurch Street to parts of East London and south Essex along the London, Tilbury and Southend line. It was the operator of the Essex Thameside railway franchise, and later rail contract, from 26 May 1996 to 20 July 2025.

After the privatisation of British Rail, the London, Tilbury & Southend railway franchise was awarded to Prism Rail, who began operating as LTS Rail in May 1996. To fulfil its original franchise commitment of replacing its slam-door rolling stock, LTS Rail ordered 44 Class 357 Electrostar electric multiple units (EMUs) in 1997; an additional order two years later saw the replacement completed by 2003. During 2000, LTS Rail rebranded as c2c, the same year Prism Rail was acquired by National Express.

The original franchise was scheduled to conclude on 26 May 2011, but received multiple extensions before National Express was awarded a second franchise in 2014. Various service changes and amenities have been introduced over the course of the two franchise periods, including the fitting of regenerative braking to its rolling stock (the first UK train operator to do so) in March 2007, the launch of Quiet Zones onboard its trains in early 2008, the provision of Wi-Fi in April 2017, and the rolling out of pay-as-you-go and National Rail ITSO smartcard ticket options over multiple years.

In February 2017, National Express sold c2c to Trenitalia. During December of that year, c2c announced an order with Porterbrook for six 10-car Class 720/6 Aventra EMUs in response to growing demand; they were introduced as twelve 5-car units in September 2023. Largely in response to the COVID-19 pandemic, the franchise agreement was replaced by a rail contract on 19 July 2021 under which services have continued to be run. In February 2023, the Department for Transport (DfT) announced the extension of c2c's contract through to July 2025. c2c was one of several train operators impacted by the 2022–2024 United Kingdom railway strikes.

The company was renationalised and taken over by DfT Operator when its contract expired on 20 July 2025. At the time of its takeover, it had a customer satisfaction rating of 89%, one of the best in the country. The new government-owned operator continues to be known as c2c.

The London, Tilbury and Southend franchise was created as part of the privatisation of British Rail. In December 1995, the franchise was awarded to a management buyout; the handover was initially due to happen on 4 February 1996. However, on 1 February 1996, ticketing and settlement irregularities were discovered and the other shortlisted bidders were invited to tender again. In May 1996, the franchise was awarded to Prism Rail by the Director of Passenger Rail Franchising for a period of 15 years. It began operating as LTS Rail on 26 May 1996. The franchise period could have been reduced to seven years if the operator did not fulfil commitments made during the bidding phase to replace its rolling stock with new-build trains.

Passenger numbers increased above forecasts which caused overcrowding as trains reached capacity at peak times. During 1998, the franchise was renegotiated to provide for the elimination of slam-door rolling stock and increased fleet by March 2002, increased staffing of stations, real-time passenger information system, improved security measures, improved station facilities for disabled people, increased cycle storage and pedestrian access from Chafford Hundred railway station to Lakeside Shopping Centre.

LTS Rail started serving West Ham from 14 May 1999 to coincide with the opening of the Jubilee line extension. Peak services were restricted at West Ham, because of limitations of the signalling system. These were eliminated in time for the December 2011 timetable change ahead of the 2012 Summer Olympics.