Deloitte has raised concerns that English Premier League (EPL) clubs are spending too much of their revenue on wages, following the publication of its Annual Review of Football Finance.

During the 2008-09 season, the 20 top-flight football clubs posted a £49m increase in revenue - less than half of a £123m increase in wage costs as the competition's overall salary bill hit more than £1.3bn. According to Deloitte's Sports Business Group, wage growth is expected to "outstrip" revenue increases yet again for the 2009-10 season and warned that the trend is unsustainable.

Alan Switzer, partner in Deloitte's Sports Business Group, said: "We expect wages growth to outstrip revenue increases again in 2009-10. This will further reduce operating profitability, a decline that cannot continue indefinitely. "However, clubs have the opportunity, via the revenue uplift from the new broadcast deals from 2010-11, to get wage levels down to a more sustainable share of revenue. It's not the first such opportunity. It remains to be seen whether they grasp it."

Meanwhile, Annual Review of Football Finance revealed that the 92 Premier League and Football League teams posted a £100m increase in revenues to more than £2.5bn during the 2008-09 season. EPL clubs' revenues reached £1.98bn and Deloitte said it is expecting that figure to reach £2.2bn for 2009-10, although the study found that the German Bundesliga is now more profitable than its English counterpart.

Sports Business Group partner Dan Jones said: "Despite the sharp economic contraction, Premier League clubs were able to increase revenues by 3 per cent in 2008-09. "For the 2009-10 season just ended, combined attendances for the Premier League and Football League exceeded 30 million - a level not seen since well before the introduction of all seated stadia."