Health club operator Fitness First has identified Birmingham as a potential growth area as it looks to expand its global operations.

The company, which already operates several centres in the city and more in the West Midlands, has posted an 18 per cent jump in annual earnings and announced it is on track to match the 49 clubs it opened last year.

The location of the new sites is a closely guarded secret, however, the group is looking to exploit developing markets abroad, while domestically the growth opportunities offered in large conurbations such as Birmingham are considered to be very appealing.

A company spokesman said: "No locations have been pinpointed but major conurbations such as Birmingham are of interest to the company."

The group, which now operates 501 sites in 16 countries, has announced total revenue increased 15.5 per cent – up 4.2 per cent on a like-for-like basis – to #463.4 million for the year to the end of October.

Underlying earnings were up to #111.6 million as the privately-owned company said it was in "great health".

Growth stems from the company’s network of new clubs, as well as a significant improvement in membership retention rates. Membership globally now stands at 1.4 million. UK membership numbers were ahead 11.5 per cent at 433,038.

The company said its performance indicated it was on track to open in the region of 50 clubs in the current financial year, including in new markets such as India.

Fitness First is increasingly diversified, with continental Europe accounting for 36 per cent of revenues, UK making up 31 per cent and Australia 21 per cent.

A total of 49 new clubs were opened during the previous financial year, including the acquisition of 21 sites in seven transactions. One of these involved the #11.4 million purchase of the Fitness Exchange chain, comprising ten clubs, which boosted the company's presence in London.

Colin Waggett, chief operating officer, said: "Fitness First is in great health and continues to grow at pace.

"Membership retention rates are up significantly as we continue to improve the quality of our sales, and enhance the service we offer to our members."

Mr Waggett said the company was now well positioned to take advantage of the global popularity of the health and fitness ethic.

"Fitness First is on track to open in the region of 50 clubs this year and is very excited about opportunities in new markets, specifically India," he added.

It also emerged that Mike Balfour, who founded the business, has stepped up from deputy chairman to become co-chairman alongside Stefano Quadrio Curzio of BC Partners, the private equity firm with a controlling stake in the business.

The company’s UK operation achieved revenues of #142.7 million from 179 clubs last year. The turnover figure was up five per cent.