The exclusive deal with the game's publisher Havas will make it available through gameplay's web site ( www.gameplay.com ), its digital television tie-ins with Open, Telewest and ntl and its eight retail stores.
Initially the game was not going to be released in the UK, but it has been extremely successful since its appearance as a free modification to Half-Life in June last year.
Gameplay has had nearly 150,000 posts to its Counter-Strike online forum and has hosted exclusive downloads and screen shots.
The computer games specialist has announced "strong like-for-like revenue growth across Europe", despite a fall in its share price.
Chairman Mark Strachan said: "Despite a shortage of PlayStation 2 consoles and the associated lift in software sales, group revenues for the half year to the end of January 2001 are expected to exceed £40 million."