The elegant Victorian building which stands on the side of the busy Leeds Road in Windhill, Shipley, is best known as the home of the former Sooty museum.

Apparently there were still boxes of old puppets hiding under stairs and in cupboards when the staff of Millennium moved in five years ago.

But, where the museum once attracted hundreds of children to the former school building, today you're more likely to see crowds of senior citizens heading for the doors.

One of Millennium's most innovative ways of making sure it is in touch with the over 50s market is by inviting scores of them to sessions at its headquarters, where they share their opinions and ideas on a range of subjects.

The information gleaned from these sessions, plus hundreds of thousands of questionnaires sent out to households around the UK, forms the basis of Millennium's research. And that knowledge has helped the Shipley company rapidly establish itself among the country's top ten independent agencies.

Millennium was the brainchild of former Damart marketing chief Martin Smith about eight years ago. Mr Smith, who was also marketing director of the SAGA Group, was convinced advertising agencies were missing a trick by failing to tap into the senior market.

"When I was working on the client side, I found it very frustrating that I couldn't find an agency that understood the needs of the mature market," said the Leeds-born managing director. "We would bring in agencies but spend half our time educating them about the market."

Research director Naomi Watkins, who joined Millennium five years ago after working for major clients like the AA and Direct Line, said part of the problem was the kind of people in charge of marketing budgets.

"If you look at most companies, then the people in their marketing departments and in advertising agencies tend to be in their 20s and 30s," she said.

"What they are interested in is selling things that their friends are going to buy and they are not interested in what they see as old people. If you asked them to think about people aged over 50, then they would immediately think of their parents or grandparents."

Mr Smith admitted that the early days for Millennium were tough.

"It is difficult starting up any new business, particularly if you have been cocooned in a comfortable corporate lifestyle," he said. "In the early days of an agency, it is very much just yourself, but I did manage to bring a team of people across from Damart." Mr Smith admitted that it was hard to get firms to listen to the Millennium message at first and found that many big clients were very reluctant to embrace a new agency in Shipley. The big breakthrough came after about two years, with a contract with the company now known as Australian Mutual Provident which took on Millennium to help it market a new equity product for the over 70s. And the message began to get through.

The statistics about the significance of the over 50s market speak for themselves.

A third of the UK population is aged over 50 and they have a collective spending power of nearly £200 billion. They hold more than 80 per cent of the nation's wealth and 60 per cent of all savings, and they dominate the market for luxury goods. Yet, according to Millennium's research, 86 per cent of them don't relate to advertising.

As bosses have woken up to this spending power, more and more of them have headed to Shipley to find out how best to tap into it.

"Over the last five years, there has been a growing awareness that the over 50s market is here to stay," said Mrs Watkins. "It is one of the reasons that we have been able to grow so quickly when a lot of other agencies have been struggling."

As word has spread, so Millennium has grown. When it became too big for its original base in Crossflatts, Bingley, it moved to Shipley. And in the last five years, staff numbers have grown fivefold to more than 100 and a small office has been opened in London's Covent Garden to give the firm a presence in the capital. Turnover is £12 million and growing.

Big name clients who use Millennium for market research and advertising across television, radio and the print media now include Age Concern, Kelloggs, Swinton, Cancer Research UK, Norwich Union, Axa, The Times and The Royal Bank of Scotland.

And Mr Smith said he wasn't surprised by the way it had taken off.

"Nobody has a crystal ball, but the one thing that was certain was that the demographics were going to change. So, in that sense, there's no great surprise that the market's growing and, if it's growing like that, then there's an increased need for specialised services."

Not that Millennium - which has big expansion plans for the future - is taking things for granted. The company is keen to keep track of the opinions of the 100-strong panel of older people from the Bradford area who attend sessions at Millennium, and also wants to recruit more members.

Mrs Watkins said it was vital for the business to keep track of their views.

"It's our bread and butter at the end of the day and, without their contribution, we don't know what's going on."