Very interesting thread as there are so many talented game developers in Britain (unmatched imo). These are just the ones I see as the most prominent.
Bizarre Creations (Project Gotham Racing, Blur, Geometry Wars)
Black Rock Studio (Pure, Split/second)
Bullfrog Productions (Magic Carpet, Dungeon Keeper)
Cloudgine (Crackdown 3)
Codemasters (F1, Colin McRae Rally, Operation Flashpoint, Race Driver: Grid)
Core Design (Tomb Raider)
Creative Assembly (Total War, Alien: Isolation)
Criterion Games (Burnout)
Crytek UK/Free Radical Design (TimeSplitters)
Eurocom (Crash Bash, Dead Space: Extraction, GoldenEye 007: Reloaded)
Evolution Studios (World Rally Championship, MotorStorm, Driveclub)
Firefly Studios (Stronghold)
Frontier Developments (Elite, RollerCoaster Tycoon 3, Zoo Tycoon 2013)
Ignition Entertainment (Metal Slug)
Juice Games (Juiced)
Lionhead Studios (Black & White, Fable)
Llamasoft (Gridrunner)
Media Molecule (LittleBigPlanet, Tearaway)
Ninja Theory (Heavenly Sword, Enslaved: Odyssey to the West, Hellblade)
Playground Games (Forza Horizon)
Rare/Rareware (Banjo-Kazooie, Killer Instinct, Perfect Dark, Conker, Donkey Kong: Country, GoldenEye 007, Battletoads)
Realtime Worlds (Crackdown)
Ruffian Games (Crackdown 2)
Rebellion Developments (Aliens vs. Predator, Sniper Elite)
Reflections Interactive (Driver, Destruction Derby, The Crew, The Division)
Revolution Software (Broken Sword, Beneath a Steel Sky)
Rockstar North/DMA Design (Grand Theft Auto, Manhunt, Lemmings)
Rocksteady Studios (Batman: Arkham)
Sensible Software (Cannon Fodder, Sensible Soccer, Sensible Golf)
SCE Studio Liverpool/Psygnosis (Wipeout, Formula One, Colony Wars)
SCE London Studio (The Getaway, SingStar, The Playroom)
SCE Team Soho (The Getaway, Dropship)
Splash Damage (Enemy Territory: Quake Wars, Brink)
Stainless Games (Magic: The Gathering – Duels of the Planeswalkers)
Sumo Digital (Sonic & All-Stars Racing Transformed, LittleBigPlanet 3)
Team17 (Alien Breed, Worms)
The Chinese Room (Amnesia: A Machine For Pigs, Dear Esther, Everybody's Gone to the Rapture)
Traveller's Tales (Mickey Mania, Lego games)
Edit: If I had to choose my favorite British gaming franchise would be Tomb Raider...... and LittleBigPlanet, Grand Theft Auto, TimeSplitters, Cannon Fodder and The Getaway.
