The two franchises are for Essex Thameside, which will be for 15 years, and the new Thameslink, Southern and Great Northern (TSGN) operation, which will be for seven years. The deadline for bids is December 24. Both franchises will begin in September 2014, except that Southern services will not be integrated into the TSGN franchise until July 2015.

"These are the first invitations to tender to be issued since the independent Brown review into rail franchising, which endorsed the government's approach to the railways," says rail minister Mr Simon Burns. The government says it looking for "ambitious and innovative" bids, and that it will evaluate and value quality. The DfT says it wants bids that "demonstrate the intention to innovate technically, operationally and through novel business models." Bidders will be allowed to exceed the DfT's minimum requirements in all areas.

The Essex Thameside franchise is currently run as C2C by National Express, which won a two-deal in May to continue operating it. C2C provides commuter services between London Fenchurch Street, Southend and Shoeburyness.

The TSGN franchise will be the largest British railway franchise ever let. It will combine the existing Thameslink and Southern franchises encompassing services running from Bedford, Peterborough and Cambridge through central London to Gatwick Airport, Brighton, Portsmouth, Southampton and Hastings. "It will have the greatest passenger numbers, the highest income and the most trains and staff of any franchise," says the DfT.

It will also be a very challenging franchise as it encompasses the £6bn Thameslink project to improve services in London on the core section between St Pancras, Farringdon, Blackfriars and London Bridge. Blackfriars station has already been rebuilt but the reconstruction of London Bridge has only recently started. Siemens is building a new fleet of trains for Thameslink, and automatic train operation will be introduced to reduce headways on the core section. The Thameslink project is expected to be completed by December 2018.