Townleys' offices in Islington feel more like a locker room than a law firm. Solicitors from the UK's top league sports law practice are visibly more relaxed and laid back than their City counterparts.

But then, the very nature of their work means that Townleys solicitors do more of their networking over a few pints than a plate of pasta in an upmarket eatery. Although when it comes to performance they are, like their clients, deadly serious.

Set up by former shipping lawyer Stephen Townley in 1983, the firm has enjoyed a year on year increase of 15-25 per cent in revenue.

The practice has acted for more than 40 different types of sports ranging from long distance walking to dog sledding. Clients include the Rugby World Cup organising committee, the International Tennis Federation and football teams in locations ranging from London to Moscow.

From having several solicitors a decade ago, the firm now has 16 lawyers and five trainees, with Darren Bailey recently being appointed the firm's fifth partner. Bailey, who signed for Chelsea Football Club at 14, says the firm acts largely for “rights owners” – the governing or regulatory bodies of sports organisations which are facing increasingly stroppy and powerful players.

“The fundamental shift in sport has been a shift in society itself,” says Bailey. “There is far less deference from sports people to administrators.”

He adds: “Our job is to keep the sports [we represent] out of the court.”

Townleys has a somewhat Corinthian attitude to sport – preferring to remain on the sidelines and play a “constructive legal role”. Still, its largely rights-only client base means it can afford to take this stance.

The firm's success in the legal marketplace can be measured by the sometimes negative and contradictory comments it gets from rivals. One said Townleys solicitors were extraordinary self-publicists. Another rival said the firm did not publicise itself enough.

Perhaps a certain kind of truth comes from another sports lawyer who has just come back to the legal profession. In appropriate sporting parlance, he says you just “can't go past them”.

Townleys partner Nic Couchman seems relaxed about the fierce sporting competition that is emerging from City firms, but then you suspect Couchman would be laid back even if you told him he was the opponent for Mike Tyson's come-back fight.

For now Townleys is not cocky, but the firm does exude the confidence of a team on top of its game.