THE £800 million sale of Poole-based Fitness First - the world's second largest gym operator - has taken another step forward.

The largest gym operator in UK and Europe is now officially listed as up for sale by the City's Takeover Panel which regulates the process.

In June the Echo reported that Fitness First's majority shareholder, private equity firm Cinven, was selling the world's fastest growing gym group for £800 million exit in a deal expected to take four months.

Cinven's planned exit is swift. It paid £400 million to buy First Fitness out of the stock market just two years ago in April 2003. The City had expected it to be sold or refloated on the stock market after around five years.

The new deal is expected to mean a second windfall for deputy chairman Michael Balfour. He reportedly made £11 million from the first sale of the business to Cinven and stands to make much more this time.

Fitness First operates 416 gyms across the world with membership topping the one million mark.

In 12 years, Fitness First has grown from a suburban Bournemouth gym to a business empire that stretches across 15 countries.

It was started in 1993 by Mr Balfour and fellow entrepreneur Christopher Pearce. Three years and six clubs later, Fitness First was the first health and fitness company to float on AIM with Mr Balfour as managing director and Mr Pearce as executive chairman. This provided the funds to roll out the chain.

In 1998 Fitness First became the first UK health club operator to enter continental Europe. In 2000 the business expanded into Asia and Australia. Two years ago Fitness First was bought out of the stock market by Cinven. John Lovering became chairman and Christopher Pearce moved to a non-executive director role.

In August 2004 Mr Balfour stepped down as chief executive to become deputy chairman. He remains involved at board level. Mike Metcalf, previously CEO at Burberry, became chief executive.

There are now 166 Fitness First clubs in the UK, 168 in continental Europe, 40 in Asia and 41 in Australia. Fitness First will open in Dubai in late 2005, with more expected to follow in the Middle East and North Africa.