The Kent Film Office has boosted the county's economy by around £30m in almost five years, figures reveal.

Les Miserables, Great Expectations and Call the Midwife are among the county's top grossing productions from April 2011 to last month.

Some of the most popular sites used by crews include Chatham Historic Dockyard, the White Cliffs of Dover and Penshurst Place near Tonbridge.

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Gabrielle Lindemann, film officer at Kent County Council, said: "The Kent Film office is there to bring investment into the county from film and TV activity.

"We don't physically get the money - the money gets spent with businesses in the county, through location fees, hotels, meals, transport, materials, wages and that kind of thing."

She added: "We think it's quite an important part of the Kent economy because all of the money gets spent directly with residents and businesses and of course the healthier the economy is, the better it is for the county."

Kent has more than 500 registered sites available to crews from around the world.

However, the Kent Film Office maintains close contact with the Kent Wildlife Trust as well as every parish and district council, and National Trust site to ensure no filming opportunity is missed.

It also ensures the database is not clogged with millions of images, making it more difficult for location managers to view potential hotspots.

Watch: The films making Kent millions

The process involves images being sent out to location managers and if interest is expressed, a recce can be arranged.

The fees for each company range from hundreds of pounds to hundreds of millions of pounds – but the final figures are based on the production company's budget and their estimated spend in Kent during filming.

Ms Lindemann said: "We do send out a spend sheet where we actually ask production companies how much they have spent. We get a fair amount back and from that we work out an average for that type of production.

"It's not only the Kent Film office that does that but Creative England do so nationwide.

"So, they ask every production in the UK what they spend on a certain production per filming day and they work out averages which are published every year and they get ratified either by the British Film Institute or the Production Guild and they then ask them whether these are reasonable figures. They then get published annually and shared with us.

"It's quite an important part of the Kent economy because all of the money gets spent directly with residents and businesses" - Gabrielle Lindemann, KCC film officer

"So when a company doesn't fill in a production form, we go back to those average figures that Creative England publishes and we use them instead."

From 2011 to 2012 the Kent Film Office estimated £2.6m had been spent. The year-on-year figures then jumped to £7.3m, followed by £9.3m. The latest figures from 2014 to 2015 sit at £6.7m.

Ms Lindemann doesn't feel the numbers are necessarily an indication of success though.

She said: "In some of the years we had The Tunnel, which was an Atlantic drama, based entirely in the county. They spend roughly about £5m when they are here.

"You only need a Warner production here for just a month or so and they spend an enormous amount of money."

One of Kent's most well-known filming locations is Chatham Historic Dockyard which has been featured in films, TV features and dramas including The Mummy, Downton Abbey and Foyles War.

Nigel Crisp, film liaison officer, said: "Normally film companies that approach us have already worked here before and we also get some referrals from the Kent Film Office.

"The office is very important to us as it puts Kent out as a destination for filming. It's important that somebody is pushing the county as a location for all productions."

He added: "It's very important to the local economy. Obviously we get a fee for the filming but it's important that when crews are here for several days, they're staying in local hotels, and they're out in the evening spending money in the local towns.

"It's very important not just for the filming but also for the knock on-effect.

"We do film location tours now on site and Call the Midwife tours so there's a follow up even when the films are gone, bringing money into the local economy."

The site was once a royal and naval dockyard, which visitors are still reminded of thanks to its nautical features. It is also home to 43 monuments and original buildings which some production companies would struggle to find elsewhere.

Mr Crisp said: "A few years ago, Call the Midwife could have filmed in London quite happily. They can't now as the places they would have filmed in have been demolished or altered so they come here to get the authentic feel."

The award-winning period drama is one of thousands of productions which have had to go through the Kent Film Office since it began running a decade ago.

With an average of 400 to 500 requests each year and around 600 to 700 filming days available annually, based on all available locations, it is safe to say Kent will continue to feature on both the small and big screens for years to come.