When the economic weather changes, businesses, like plants, need to react fast. And when the real weather changes the same applies — particularly if your business happens to be concerned with swimming pools.

At Certikin International, of Witney, Britain's biggest supplier of pool equipment, they know all about that. The company is this year celebrating its 50th birthday, having swum through plenty of peaks and troughs of both sorts of weather.

Now, despite tough economic times, it employs about 105 people: 85 in Witney and 20 in Leeds (though that number varies slightly with the seasons) and turns over about £26m a year.

Managing director Neil Murray said: "Turnover is static at the moment — which is quite good in this market; particularly with the long, cold spring we have had. Like ice cream, people buy pools in hot weather."

He added: "Back at the start of this recession in 2008 we laid off eight people. Since then we have have been prepared to cut back everything except the people. We realise our workforce is our lifeblood. Some have been with us for 25 years and we know their experience and technical knowledge would be hard to find again.

“And of course we want to remain the dominant brand in the country — which we are by a factor of about four."

But how much are people buying swimming pools — and swimming pool equipment — in belt-tightening times like this? After all, surely pools are the very essence of fun and luxury; just the sort of thing that people, even those aspiring to such lifestyles, would quickly assign to the dream department?

Mr Murray said: "There are basically two kinds of pool: those lined with durable plastic which are, if not cheap, at least 'more affordable' and at the top end concrete pools which are more expensive.

“In this recession it is the liner pools sales which have fallen off. And we decided early on to concentrate on the top end, where there is more value added."

Seemingly there are still plenty of people about so rich that, in Mr Murray's words, their pool constructing ambitions are "limited only by their imaginations."

Another indicator perhaps that in this down-turn the rich are still very much with us, with their spending filtering down through the the economy to the rest of us.

To mark the company's 50th anniversary prime minister and Witney MP David Cameron visited Certikin's manufacturing and warehouse facilities in Witney's Station Lane Industrial Estate.

He said: "Not only does Certikin International bring jobs and a real boost to our local economy here in West Oxfordshire but the company also brings business and manufacturing to Britain.

"It is businesses like this which are helping to lift our economy out of a very difficult time and making sure that Britain thrives in the global race. I wish them every success for the future.”

But whatever the future may hold, Certikin certainly has an interesting past.

The original company came into being in 1963 in a basement in Horsham, Sussex, supplying products such as chlorinators and diving boards.

Coincidentally, and at about the same time, the late landscape gardener Peter Geekie, one of the best known figures in the world of post-war swimming pool development, established a swimming pool display area at his garden centre on Cumnor Hill, Oxfordshire; the first such display of above-ground pools in the UK.

By the end of the decade he had won the Oxfordshire County Council contract to supply schools with pools.

However, as it became apparent that public and private pools were becoming ever more popular, and that more and more pool manufacturers were starting up, Mr Geekie realised that although the industry was becoming fragmented there was money to be made by distributing and manufacturing the supplies that every pool owner or pool builder needs, such as chlorinators, heat pumps, inlets, underwater lights and so on.

He formally set up Peter Geekie Pools in 1971 and five years later, during the the long hot summer of 1976, saw the company double in size.

But in 1980 he split the activities of pool building and wholesaling into two separate entities: the firm that is now Certikin focussed on wholesaling, while the businesses of pool building and retailing were put into the hands of what is now Oxford Pools, of Swinford, next to the toll bridge, (now a completely separate firm to Certikin).

Mr Geekie sold the Oxfordshire supplies business in 1990 to chemical giant Ellis and Everard plc.

Certikin and Peter Geekie's former pool supplies business merged in the Witney premises in 1992. After a further series of takeovers, it became part of Spanish multi-national Aquaria in 2003 .

Now Aquaria has been renamed Fluidra and has an annual turnover of more than £400m — with Certikin supplying more than 3000 products to the industry, many made in Witney.

Mr Murray, who joined the enterprise in 1990, said: "Now there are Certikin branded companies in Dubai and India as well as separate Certikin firms in Spain, France, Italy and Portugal.

“It is astonishing how the industry has progressed over the years. In the beginning the first underwater lights, for instance, were converted car headlights.

"Now some London houses have pools in the basement with moveable floors covering them so the space can be an extra room when needed."

About 15 per cent of Certikin's market is export, with product going to more than 50 countries.

It supplies equipment and expertise to domestic and commercial customers including operators of Wellness centres, spas and water parks.

Mr Murray told David Cameron: “Certikin bears testament to the fact that from acorns, oak trees grow."

As for that old worry of the weather, the company is trying to address that by marketing the Endless Summer Enclosure, a ‘telscopic’ roof that enables a pool to become indoor or outdoor at its the owner 's whim.

All the same, Mr Murray is hoping for a fine, hot summer after that cold winter.

He said: "This business is about fun and sunshine. But in the end people come to us because we provide top quality in all we do."