THEY are giants in our midst - in Weymouth alone there are several. We drive past them every day and they employ hundreds of people. But how much do we know about the world behind the gates of our holiday camps?

To find out more, I spend a morning at Weymouth Bay Holiday Park in Preston.

The 90-acre site forms a mini-empire of 800 caravans at Weymouth Bay and 250 at adjoining Seaview (holidaymakers visiting one can use the facilities of the neighbouring park).

Weymouth Bay, almost a village in itself, also boasts two swimming pools, two adventure playgrounds, shops, eateries and a show-bar' that provides non-stop family entertainment.

There are even character breakfasts à la Disney World.

It is all a long way from where British caravanning holidays started off.

Site maintenance manager Stephen Wheeler has worked at the park for almost 30 years - he helped build the club - so he, more than anybody on site, has seen some changes.

"Now all of them have got central heating and toilets, but when we first came here it was toilet blocks and they had to go out to get water. It was like a big version of a touring caravan," he said.

Caravanning has changed over the decades, perhaps because as consumers we have grown more demanding.

My childhood holidays were spent in the middle of a wet field in west Wales with no entertainment but board games and the joy of familial company.

In peak season at Weymouth Bay, the 250 seasonal members of staff look after the guests at every stage of their holiday and provide round-the-clock entertainment for the children.

Stephen said: "I've seen a lot of changes over the years like with the entertainment and the swimming pools, and it's the same with caravan ownership."

The privately-owned caravans in the holiday park number around 600 and cost between £20,000 for the more basic models and £70,000 for the platinum' caravans at the top of the range, which have heating throughout, free-standing furniture and luxuries like microwaves and DVD players.

Weymouth Bay sublets them for owners should they require that service.

Weymouth Bay and Seaview are now owned by Bourne Leisure, a British company formed in the 1960s that handles Haven, the group that covers Weymouth Bay, British Holidays, Butlins and Warner Leisure Hotels.

Stephen said: "Bourne Leisure has got 36 parks around England, Scotland and Wales and we've never been as good with bookings."

It is curious, when you think about it, that you take an idea like the caravan, the original mobile home, and take away the mobility and it is still an enormous hit.

But this year - with the credit crunch and pound weak against the Euro - the British seaside holiday is doing better than ever.

General manager Neil Ankers said: "The credit crunch and the cost of flying are having a positive impact on the seaside holiday market."

"Even last summer," he adds, referring to the rain, "people still came, we normally work on occupancy rates of 95 per cent. People do book in advance. It's a little bit more challenging for them to enjoy themselves if it rains. They will spend more time in the park as most of our main facilities are under cover."

But, wet weather aside, Neil feels that criticisms that the holiday parks are self-contained are not fair.

"They are not just going to stay here for the week. They will explore local restaurants, local pubs and local sights. Think of all the local tradespeople that we use to carry out work in the park.

"Caravan holidays are the traditional holidays in the UK. They have been going for decades.

"I think it's important we fit in, but, equally, it must be acknowledged that we are supplying 4,000 guests per week, plus owners, into Weymouth and that they impact on the local economy, and that we employ 250 people as well."

Building bridges between the holiday park and the local community is a priority at Weymouth Bay at the moment.

Allen Main, the holiday park's press and marketing officer, is involved in this drive.

"There was quite a negative picture before," he told me. "We have invited local residents to use our facilities and we have opened our nature walks so they can bring their dogs there.

"It's all about making sure they are happy, warning them about noise, things like that. And we've got a lot of borders, where the park is joined with residents' gardens; we'll go and deal with the environment there as a lot of the residents are elderly."

In addition to this, Weymouth Bay has sponsored local football teams, donated to the village hall, upgraded its sponsorship of Dorset Wildlife Trust to corporate membership and is working alongside the RSPB on various initiatives on the site.

Certainly the staff at Weymouth Bay seem happy where they are.

"I could never work in another environment," said Allen. "I've always worked in holiday parks."

Last year Bourne Leisure was chosen by the Sunday Times as one of the top 20 best big companies to work for in the UK, coming in at number 15.

The company offers incentives such as use of the site facilities and on-site entertainment, team member accommodation at some sites (this is the case at Weymouth Bay), a bonus scheme and performance awards, a nationally recognised customer service programme, NVQs, and up to 25 per cent off holidays within the group.

In the hustle and bustle of the staff office, someone passing tells me: "Working here is like Marmite, you either love it or you hate it."

But everyone I speak to seems to thrive in the high-pressure environment.

"It takes a certain personality, one that gets a buzz from it," said head of housekeeping at Seaview Debbie Wells, who followed in the footsteps of her late mother Pat Batchelor in the job; she was head of housekeeping at both holiday parks.

"We've got 240 cleans to do tomorrow. It's a challenge, but it's a tremendous buzz."

One department that enjoys, and supplies, a buzz is the entertainment team.

Assistant entertainment manager Zippy Davies explained: "Some people come from dancing backgrounds, but mainly you need to be bubbly and able to speak to people.

"Lots of people who have done entertainment go on to the West End and things like that. You have to go through quite rigorous auditions."

Holiday sales manager Katie Watson started her working life in holiday parks doing cabaret.

Katie and her team on reception look after the owners that sublet and all the guests that come into the park.

They take bookings, greet guests on arrival and look after every aspect of their stay.

"Between the two parks last year we had 25,000 arrivals," she told me.

One problem that the park faces with its staff is seasonality; it opens from March 1 until January at which point it closes for eight or nine weeks for reinvestment over the winter.

Only a fifth or a quarter of the staff body is permanent, the remainder is seasonal.

"One of the worst parts at the end of the season is letting people go," said Katie, who helps members of her team to find work over the winter.

Nevertheless, most people seem to keep coming back.

As for what it is like working in an environment where people are permanently on holiday, Katie smiled: "It is hard work because we want people to have a nice time."