Thameslink, Southern and Great Northern (TSGN) is a management contract for the provision of passenger services on the Thameslink and Great Northern routes to Bedford, Luton, Peterborough, King's Lynn, Cambridge, London King's Cross, London Moorgate, Sutton, Wimbledon and Brighton, as well as the whole Southern network (including the Gatwick Express) and the jointly operated First Capital Connect Southeastern services (for example the Kentish Town – Sevenoaks via Catford), which were added to the franchise on 25 July 2015, with the Southern and Gatwick Express brands retained.

[4] In March 2012 the Department for Transport announced Abellio, FirstGroup, Govia, MTR and Stagecoach had been shortlisted.

[6] In January 2013 the government announced it would be exercising an option to extend the existing contract until March 2014.

[10][11] Now operated by Govia subsidiary Govia Thameslink Railway, the former First Capital Connect parts of the franchise returned to their former brand names Thameslink and Great Northern while the existing Southern and Gatwick Express brands were retained.

[17] In March 2022, GTR was given a direct award contract by DfT, replacing its franchise agreement, expiring on 1 April 2028.