Revenue grew at the West Midlands’ four top flight clubs to a healthy combined £293.8 million, new research shows, but mystery continues to surround Birmingham City and Coventry City’s finances.

Despite a year of mixed fortunes on the pitch football clubs in the West Midlands have posted record combined sales of £293.8 million, according to the 21st Annual Review of Football Finance from the Sports Business Group at Deloitte.

Aston Villa, West Bromwich Albion, Stoke City and Wolves all posted revenue growth according to the data, taken from 2011 accounts. However, the result is somewhat skewed, as a failure to post accounts by Birmingham City and Coventry City means the overall West Midlands figure fell from £311.7 million last year.

The research found that Premier League clubs’ combined revenue reached a record £2.27 billion in 2010/11, driven by a rise in broadcasting revenue, while in total, the top 92 clubs in English football saw revenues increase by nine per cent to £2.9 billion.

Meanwhile, Midland teams West Brom and Wolves – who have since been relegated to the Championship – were part of a profitability revolution in the Premier League.

The pair were among eight teams to post a pre-tax profit, compared to just two the year before, as a climate of austerity starts to tell on the national game.

West Brom were the third most profitable club, with a pre-tax profit of £18.9 million, the report shows, while Wolves were in the black by £2.2 million, making the Molineux club the seventh most profitable top flight side.

Villa took the top spot in the West Midlands when it comes to revenue, posting annual sales of £92 million – significantly more than other top flight sides.

However, the results show a wage bill of £94.8 million for the year, which contributed to a pre-tax loss of £54 million.

Indeed, Villa’s wages were significantly more than Wolves (£37.9 million) and West Brom (£43.9 million) combined, which may explain a push by the club to cut back on player pay during the short tenure of recently-departed manager Alex McLeish.

Meanwhile, League One side Walsall saw their revenue remain stable at £5.4 million.

Overall, more than 80 per cent of the Premier League clubs’ revenue increase was spent on wages, which increased by14 per cent to almost £1.6 billion, and resulted in a record Premier League wages/revenue ratio of 70 per cent.

Dan Jones, partner in the Sports Business Group at Deloitte, said: “Top clubs in English football have continued to show impressive revenue growth despite a difficult economic climate.

“Premier League clubs’ revenues increased by 12 per cent in 2010/11, driven by broadcast revenue increasing by 13 per cent, to £1.18 billion, in the first year of a new three year broadcast cycle. This uplift was primarily due to an increase in overseas broadcast deal values, demonstrating once again the Premier League’s unrivalled global popularity.

“Commercial revenue grew by 18 per cent during 2010/11, although this was largely attributable to clubs with a more global profile. Matchday revenue increased by £20 million to £551 million, however almost half the clubs suffered a reduction in matchday revenue in 2010/11.”

Revenue in the Football League Championship increased by £17 million – or four per cent – to £423 million, prompted by an increase in the solidarity payments from the Premier League and the promotion of some larger clubs into the division.

Of the £2.4 billion net debt in the Premier League, £1.5 billion is in the form of non-interest bearing “soft loans”, of which almost 90 per cent relates to three clubs - Chelsea (£819 million), Newcastle United (£277 million) and Fulham (£200 million).

On the positive side of the balance sheet, Premier League clubs recorded a carrying value of tangible fixed assets of almost £1.9 billion.