By Darren Waters BBC News entertainment reporter

In the fourth of a series of occasional interviews with key players in the entertainment industry, the BBC News website speaks to Charles McDonald, co-founder of public relations agency McDonald and Rutter.

The media had a feeding frenzy over Jude and Sienna

Each year between 400 and 500 feature films are released in British cinemas, generating about �800m in box office ticket sales.

It is a highly-competitive market and the third most valuable in the world.

Film distributors in the UK spend about �20m a month to convince you to see their films - using TV, radio, online and media adverts and posters on every space imaginable.

But there is another weapon in the armoury for film companies - public relations.

Charles McDonald, the co-founder of PR firm McDonald and Rutter, is one of the UK's leading PR figures and it is his job to convince you to see his clients' films.

He regularly works with directors such as Mike Leigh, David Lynch and Anthony Minghella, helping to promote films which he calls "art house potential blockbusters".

There is an attempt to be a little bit more controlling on the part of the industry Charles McDonald

Mr McDonald has masterminded campaigns for films such as Vera Drake, The Hitchhiker's Guide to the Galaxy, Amelie, Gosford Park, The Pianist and Lost In Translation.

The company will also be looking after the campaign for the forthcoming release The Constant Gardener, one of the early hot tips for an Oscar in 2006.

"We don't take ourselves enormously seriously - that's not to say we don't approach it in a professional way," says Mr McDonald of his firm's attitude to PR.

"PR is a very cost effective way of getting your message out there. These messages do need to be controlled with a small 'c'."

Siphon access

The issue of control is an important one in all publicity. Access to stars for interviews, visits to film sets, exclusive photos and information - PR companies are increasingly careful about how they siphon access to stars and their films.

The Constant Gardener is being tipped for Oscar success

"There is an attempt to be a little bit more controlling on the part of the industry - whether that's a good thing or not I'm not sure," says Mr McDonald, who set up his firm in 1994.

"The situation here is still very different to how it is in America. The media there are generally more open to the idea of - shall we say - suggestions from PR people.

"I welcome the fact the media here isn't perhaps as led by - certainly in the entertainment world - the individual publicists as they are in America."

In the US many stars have personal publicists who tightly control access to their clients, and bestow interviews to a select group of journalists on select publications.

Readers are often oblivious to the deals that have been struck to secure that access: a positive review and a fixed amount of coverage are not unusual demands.

'Commercial prerogative'

"It's inevitable that some deals are being done these days," says Mr McDonald, who says he never strikes such deals himself.

"I think it's true to say we are moving in that direction and as much as anything else that is the commercial prerogative. There is a pressure on magazines, for example, to get the stars that they want in the edition or featured on the cover."

Access to stars is carefully controlled

But Mr McDonald feels the UK is still some way off the controlling attitude.

"I think the media are getting fairly genuine access to stars," he says.

He adds that while there is a coterie of people and publications in the UK who have a strong influence on how a film is received, it is more complex than that.

Timing is crucial in any PR campaign for a film, he says.

"With a production these days it's getting harder and harder to get access for journalists on to the set of a film - which I have to say I totally understand and sympathise with.

People resist being told over and over again that a film is fantastic Charles McDonald

"It's very difficult to ask an actor to sit down with a journalist and do a decent interview when actually on set, when they are trying to concentrate on what they are doing."

He says a campaign is a question of "assessing who is in the film, what the film is, what kind of film it is, whether it will benefit from early exposure or whether it might even be damaged from early exposure".

Campaign

McDonald and Rutter is currently working on a campaign for Anthony Minghella's new film Breaking and Entering, starring Jude Law and Juliette Binoche.

"With the cast he has got there really isn't a huge amount of point in trying to hype it.

"You have to think of yourself as a punter and work out the level at which coverage becomes too much and becomes counter-productive.

"People resist being told over and over again that a film is fantastic."