| Eutechnyx | 1987 | 3 | — |
| Evil Twin Artworks | — | 1 | — |
| Evolution Studios | 1999 | 6 | — |
| Excalibur Games | March 14, 1997 | — | 1 |
| Excalibur Publishing | — | — | 5 |
| Exient Entertainment | 2001 | 1 | — |
| Failbetter Games | 2010 | 1 | 1 |
| Feral Interactive | 1997 | 22 | 29 |
| Fiendish Games | December 20, 1999 | 2 | 1 |
| Firebird Software | 1984 | — | 3 |
| Firebrand Games | 2006 | 4 | 1 |
| Firefly Studios | 1999 | 9 | 4 |
| Fireproof Studios | — | 6 | 6 |
| Fireshine Games | August 12, 2009 | — | 9 |
| Firestoke | February 16, 2021 | — | 2 |
| First Touch Games | May 18, 2011 | 2 | 2 |
| Five Aces Publishing | November 3, 2014 | — | 5 |
| Flair Software | 1990 | — | 1 |
| Flaming Fowl Studios | March 16, 2016 | 2 | — |
| Friv | 2006 | — | — |
| Frontier Developments | 1994 | 16 | 15 |
| Full Fat | 1996 | 3 | — |
| Funbox Media | March 10, 2010 | — | 2 |
| Future Friends Games | 2017 | — | 1 |
| Gaming Company | October 23, 2014 | — | 1 |
| Ghost Town Games | March 6, 2015 | 2 | — |
| Ghostlight | 2004 | — | 4 |
| Good Gate Media | 2018 | 1 | — |
| Grandslam Entertainments | 1987 | — | 4 |
| Graphic State Games | 2000 | 3 | — |
| Great Detail Ltd | — | 2 | — |
| Gremlin Interactive | 1984 | 15 | 12 |
| Grey Alien Games | 2004 | 3 | 21 |
| Ground Shatter | May 23, 2014 | 3 | 1 |
| Guerrilla Cambridge | 1997 | 7 | — |
| Hanako Games | 2003 | 3 | 3 |
| Headfirst Productions | 1998 | 1 | — |
| Headstrong Games | 2008 | 2 | — |
| Headware Games | — | 1 | — |
| Hewson Consultants | 1984 | — | 2 |
| HexWar Games | — | 5 | 5 |
| High Tea Frog | — | 1 | 1 |
| Hodder & Stoughton Limited | 1868 | — | 1 |
| HotGen | 1999 | 4 | 2 |
| Hothouse Creations | 1996 | 1 | — |
| Hound Picked Games | June 22, 2018 | — | 1 |
| Humble Grove | — | 1 | — |
| Hunted Cow Studios | — | 1 | — |
| Hutch Games | July 4, 2011 | 1 | 1 |
| Ideaworks Game Studio | 1997 | 3 | — |
| Idigicon Limited | 1980 | 1 | 3 |
| Image Works | 1988 | — | 4 |
| Imagine Software | 1982 | — | 1 |
| IndieRevo | — | 1 | 1 |
| Infinite State Games | July 17, 2013 | 1 | 1 |
| Inkle | November 2011 | 6 | 4 |
| Intelligent Games | 1988 | 5 | — |
| Introversion Software | 2001 | 1 | 1 |
| IWare Designs | September 24, 2010 | 1 | 1 |
| Jagex | 2001 | 6 | 6 |
| Jester Interactive | 1997 | 1 | — |
| Jumpship | January 19, 2017 | 1 | 1 |
| Just Add Water | 2006 | 1 | — |
| Kaizen Game Works | 2018 | 1 | — |
| KISS | — | — | 7 |
| Koei Tecmo Europe | August 8, 2002 | — | 2 |
| Krisalis Software | 1987 | 8 | 1 |
| Kuju Ltd. | 1998 | 10 | — |
| Kwalee | 2011 | — | 2 |
| Lab42 | — | 1 | — |
| Labrador Studios | — | 1 | 1 |
| Lazy Monday Games | — | 1 | — |
| Lazyrays Games | 2019 | 1 | — |
| Level 9 Computing | 1981 | 1 | 1 |
| Lightwood Games | March 22, 1999 | 7 | 7 |
| Linux Game Publishing | October 15, 2001 | — | 2 |
| Lionhead Studios | 1996 | 10 | — |
| Llamasoft | 1982 | 1 | — |
| Lockwood Publishing | May 10, 2007 | 1 | 1 |
| London Studio | 1993 | 23 | 1 |
| Lucid Games | February 2011 | 1 | — |
| Lyrelark | — | 1 | 1 |
| Macmillan Publishers | 1843 | — | 1 |
| Magenta Software | 1994 | 2 | — |
| Marmalade Game Studio | 2016 | 4 | 4 |
| Mastertronic | 1983 | — | 6 |
| Mastertronic Group | 2004 | — | 3 |
| Matrix Games | 1999 | 1 | 14 |
| Medallion Games | February 10, 2020 | 1 | — |
| Media Molecule | January 4, 2006 | 3 | — |
| Mediatonic | September 15, 2005 | 3 | 1 |
| Micro Power | — | — | 1 |
| Microdeal | — | — | 3 |
| Midas Interactive Entertainment | 1998 | — | 3 |
| Midoki | December 14, 2011 | 1 | — |
| Midway Studios – Newcastle | 1996 | 5 | — |
| Mikro-Gen | 1981 | 3 | 5 |
| Mirrorsoft | 1982 | — | 6 |
| Mitchell Beazley International | July 1969 | — | 1 |
| Mode 7 | 2005 | 2 | 3 |