Thursday 25 November 2010, 11:38
The Arthurian legends are ripe with tales of magic and prophecy, love and hate, courage and adventure. They have a large cast of exciting characters and enduring narratives.
As such, using them as a basis for ideas is a storyteller's dream. For centuries, every generation has had their own version of the legends and I feel proud to be continuing that tradition with Merlin.
Whilst we are constantly developing the series, we've always tried to stay true to the original ethos - to tell action adventure stories for all the family that are primarily about friendship.
That hasn't changed and hopefully never will as, underneath all the monsters and magic, it is the relationships between our core characters that give each episode its heart.
As co-producer, I have a hand in pretty much every stage of the production from story lining to post production.
Every day presents a new challenge, be it deciding what language a pixie should speak, to figuring out how we physically put a sword in a stone.
Sometimes the magic behind the scenes can be just as exciting as the magic on it - such as when the special effects boys mix up their various powders to create spectacular explosions.
Other times it is slightly more mundane - the perfect rat stew, for example, is made from microwaved burgers torn up and thrown into mushroom soup.
Whatever the solution to the problem, I love being able to see something I've nursed from an idea at storyline stage come to life many months later on screen.
When we were first given the green light to make Merlin, one of the biggest tasks we faced was finding a suitable Camelot for the exterior shots. The search for the perfect location went on for some time and took us all over the UK, but nothing was quite right.
We had to set our net a bit wider and eventually ended up in France at the Chateau De Pierrefonds.
Viollet-le-Duc's showpiece of medieval architecture is as fantastical as it is magical and it was obvious from the off that this was the perfect place for us.
However, there was never any question that we could shoot the entire show in France as it would be far too expensive, so instead we visit three times a year to film all of our big exterior scenes and set pieces.
The castle is huge and we are exceptionally lucky to be able to use pretty much any part of it that we want to. Rooms such as the Salle des Preuses - which doubles as our Throne Room - are just stunning, but equally fascinating are all the underground tunnels and dusty towers - the bits the public never get to see.
It can become quite spooky though when we are shooting at night and I wouldn't recommend getting lost on your own after hours...
The most demanding parts of the year are definitely when we are filming at the ChÃ¢teau.
We run two units (what we call cast and crew together) in a day, which can mean shooting scenes from a mixture of up to six episodes.
Looking after a crew of over 200 alongside a cast of up to 20 principle actors and 100 supporting artists isn't ever easy. We have tight schedules and work long hours in all weathers so anything can happen.
However, when we're there, our home is a pretty village in Picardy, our office the castle. There are prosthetics, stunts, explosions, tournaments, croissants... it'd be a lie to say it wasn't fun.
I'm primarily on hand for all the cast and crew should they have any questions or queries about the scripts so work with everyone from costume and make up to directors and actors.
But I'm also a spare body and need to be willing to turn my hand to whatever is necessary, be that running a second unit shoot when the director is waylaid, rewriting dialogue at the last minute on set, playing nurse when people are ill, or making tea when there's no-one else to do it.
When we're not in France, we spend our time in Wales, split between the studios just outside Cardiff and various locations dotted about the countryside.
The reality of location shooting is anything but glamorous - 4.30am starts, thermals, smelly portaloos in the corner of a field - but it's always interesting.
They need to be pretty spectacular to stand up to the ChÃ¢teau, but I'd say they more than hold their own.
I have always believed in what we were making, but nothing could have prepared me for the success of Merlin. I still find it exciting to overhear people in the street or on the bus talking about that week's episode.
Without a doubt the most exciting points of each series for me are when we take iconic moments from the legends and spin them in our own way, be that meeting Mordred for the first time or seeing Excalibur forged.
This series sees more of those moments than ever - Excalibur emerging from the lake, Guinevere being crowned Queen and, for those of you that haven't guessed, we are finally bringing together that infamous group of warriors, the Knights of the Round Table.
The formation of this special group marks a new era and I can't wait to start exploring where we can take them in the next series.
But first of all you need to see how this year plays out. The final two episodes are full of spine-tingling moments - I just hope you enjoy them as much as I have.
Rachel Knight is the co-producer of Merlin.
Comments made by writers on the TV blog are their own opinions and not necessarily those of the BBC.
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