not a gamer myself, so im looking for opinon on this, but to me it sounds 
http://www.digitalspy.co.uk/gaming/a160546/tax-breaks-for-culturally-british-games.html

http://www.digitalspy.co.uk/gaming/a160546/tax-breaks-for-culturally-british-games.html
im guessing this means it has to be more than just the location, so simply setting your shoot pimps & steal cars games in London wont qualify?Games developed in the UK must be "culturally British" to qualify for tax relief.
Announced as part of the Digital Britain report, the government will provide tax breaks for "culturally British video games" much like the film industry, according to Eurogamer.
The review quotes the system in place for British movies, where those that "speak to a British narrative, rather than the cultural perspectives of Hollywood or multinational collaborations" will be given cultural tax credits.
A similar system will be installed shortly to determine what is British and in what ways titles qualify as part of the scheme.