There can be no finer setting for a festival than Henley with its idyllic position on the riverside and the quintessentially English image of beautiful buildings and summer sunshine.

But, of course, actually preparing it and making sure it runs smoothly is as challenging as it is for any event of its size.

So it comes as no surprise that it is a full-time job for Gill Mitchell, now chief executive after five years as general manager.

She explained: “I look after all the finances and I have a very small team of six who all multi-task with various different jobs.”

The festival was founded in 1983 by Roy Ackerman and Peter Coni of Kennedy Brooks, the Henley Royal Regatta’s caterers at the time.

Their thinking was that here was an event whch had marquees and grandstands up for a week that were left standing empty for much of the time, other than during the Regatta weekend.

After negotiation with the Regatta organisers, who also own the land, a deal was struck and so from the Wednesday after the Regatta to the following weekend, a variety of international performers take the stage and about 20,000 people turn up to enjoy the entertainment over the course of five nights.

The first task in the transformation of the site is to build a floating stage on the river, large enough to house a 100-piece orchestra, within two-and-half days. Doing that is a major logistical exercise.

“We have to employ the best contractors in the country — it is not a cheap event to stage,” revealed Ms Mitchell.

Ms Mitchell admits she has thought long and hard about ‘cutting the tie’ with the Regatta and finding another site could be cheaper, as ten per cent of the Festival’s takings go into the coffers of the Regatta, which is otherwise unconnected and the requirements of the two are completely different.

But the glorious riverside location is simply second to none and without it, the event just would not be the same.

Over the years the bill has included the City of London Sinfonia, Courtney Pine, Dionne Warwick, Jon Lord, Lesley Garrett, Vanessa Mae and Status Quo — a deliberately eclectic mix, according to Ms Mitchell.

Getting that mix right is a challenge for any festival organiser as it can make or break its success and over the years. This year’s line-up features pop stars Ronan Keating and Will Young, along with baritone Bryn Terfel and violinist Nigel Kennedy, which deliberately has a populist feel compared to a more classical bias of previous years, although festival-goers are still required to dress up in black ties or lounge suits at the very least.

Ms Mitchell explained: “Last year we had Katherine Jenkins who sold out, but on the Thursday evening there was a Puccini opera, one of the best we have ever done, which sold less than half its tickets.

“Our roots are as a classical event but the trouble is if you want to listen to Puccini, you are better off going to the Royal Opera House where there are excellent acoustics.

“We want to widen the appeal. Our audiences are becoming younger and the trend is for more commercial music.”

And away from the main stage there are plenty of smaller performance areas covering a vast array of musical styles from jazz to opera.

The appeal of Henley is such that many of the artists ask to come back because they enjoy the relaxed atmosphere. That also applies to the staff who work at the event, as well as behind the scenes.

“A lot of people have been with us for more than 15 years. For example, some of our security staff book holiday from their other jobs just to work at the Henley Festival.”

Anyone running a festival will tell you how difficult it is to break even, especially with the astronomical fees charged by artists.

But since the mid-1990s, Henley has actually turned a profit of between £20,000 and £100,000 a year, which is then channelled back into the local community in the form of good causes. The event turns over about £1.6m a year.

Ms Mitchell says ticket sales alone would not be enough and stresses the importance of corporate sponsorship which provides up to £600,000 of the income. This year, it features a strong line-up of national and international names including Champagne company Veuve Clicquot, finance specialists Invesco Perpetual and utility firm Southern Electric.

Guests can dine at the on-site restaurant run by Albert and Michel Roux, while listening to live music from the Jive Aces, at prices ranging between £90 and £120 a head. But the emphasis on corporate entertainment does not always sit well with locals.

Ms Micthell said: “Local people have criticised us but if we did not have the corporate people and their guests, then we we would not be able to afford to do it for everyone.

“And it is possible to see the acts, buy a cheese toastie and a bottle of water and still have change from £40. These people are the audience of the future.”

As a charity, any surplus made is donated to the Henley Festival Trust which was set up at the same time as the festival.

This funds a year-round music therapy service for the brain injury charity Headway, and SHOUT!, which has funded its own start-up children’s orchestra, the Henley Festival Orchestra, and supports a wide range of young performers and artists.

Also, the trust works with disadvantaged youngsters where music and performing can play a key part in their educational and developmental needs.

Ms Mitchell said: “If an individual or organisation has musical talent then they can apply to us for a grant.”

The recession meant 2009 was the hardest year yet for the festival, but Ms Mitchell is confident that 2010 will see Henley returning better than ever.

“We weren’t quite prepared for it — it caught us on the hop a little,” she admitted.

“But sometimes when you have a bad experience it helps you avoid becoming complacent.”