"The Department has now given 12 months notice on the current Gatwick Express franchise, which will terminate on 22nd June 2008. From this date, it will be integrated into the current Southern franchise, operated by Govia. The DfT has secured a financial agreement for the amalgamation that is at least as favourable as the existing agreements. The new agreement also secures extra peak capacity into London and a new hourly direct service between Brighton and Southampton, which Southern will introduce in December 2007.

At first, the Gatwick Express will continue as the same service as today. From December 2008, the new-style Gatwick Express service will begin. It will retain the same branding and the same frequency, with non-stop service between Gatwick Airport and London Victoria every 15 minutes. However, it will also run beyond Gatwick to Brighton at the busiest times of day, doubling the number of London-Brighton express trains in the high peak. Extra carriages for this service will be provided by the leasing of Class 442 vehicles that are currently not in use.

The combined Southern franchise will end three months earlier in September 2009. This will ensure the winner of the franchise competition is in place to implement major changes to their south London timetable in December 2009."

"The DfT will pay Govia a subsidy of £103.6m from 1/1/08 to 19/9/09 for running the Southern franchise. In 2008 the subsidy will be £71,630,000 and in 2009 the subsidy will be £31,970,746. All figures are nominal (with inflation)." (see links below.)
http://www.dft.gov.uk/press/speechesstatements/statements/gatwickexpresssouthern

http://www.dft.gov.uk/pgr/rail/passenger/franchises/gatwickexpressandsouthern