LONDON (Reuters) - Once the stuff of children’s birthday outings, paintball is attracting a growing band of devotees who see it as a competitive sport like any other, with its own international league.

The Campaign Cup started in 1989 and bills itself as the oldest paintball tournament in the world. Today, the Cup is the British leg of a competition known as the Millennium European Paintball Series, which also holds rounds in France and Germany.

This year’s British leg hosted 141 teams, consisting of about 1,500 competitors from 42 countries.

Five-player teams compete on a 45 meter (49 yards) by 36 meter pitch, roughly half the size of a football pitch, littered with obstacles behind which players shelter, as they try to reach their opponents flag station to win the game.

For a sport that focuses on shooting opponents with devices that strongly resemble firearms, devotees say that violence is not what attracts them.

“People think we’re out there and it’s like a simulation war game or something like that. It isn’t anything like that. It’s more of an extreme action sport,” said Ryan Moorhead, an American semi-professional player for the FiveStar Lleida team.

Canadian team “Edmonton Impact” were the victors in this weekend’s event - and the series moves on to Paris in September, where the European winner will be decided.