The thousands of creative decisions behind BBC Four's Dirk Gently

One man, Douglas Adams, wrote two and a half books about the adventures of holistic detective, Dirk Gently, and now over 100 people have collaborated to bring his character to the small screen for a new series which starts tonight.

Dirk Gently (Stephen Mangan) and Richard MacDuff (Darren Boyd)

The novel writer is master of his domain. Apart from odd suggestions from an editor or publisher he is king, supreme leader and dictator.

Making television is essentially collaborative and involves the creative input of a huge number of people, all of whom, to a greater or lesser degree, influence the finished product.

The producers are responsible for hiring everybody. They choose a writer (or writers in our case) to produce scripts. These scripts will set the template for all that follows but there are thousands of creative decisions still to be made.

A director is hired. Who you pick will have a massive impact on the finished product because nearly all decisions from here on in are made in conjunction with him or her.

Actors are chosen. They picked me to play Dirk but imagine the show with, say, Damian Lewis or Harry Enfield or Alexander Armstrong as Dirk instead. (If you believe any of them would have been better than me, please don't tell the BBC.)

Darren Boyd plays Richard but how different would the show be with Rupert Penry-Jones or Russell Tovey as MacDuff?

Dirk and Richard are on a stakeout

Locations for filming are chosen with the help of a locations manager, helping to find the perfect place as described in the script and if you can't find the right place you might build a set, which has to be designed, built, decorated and furnished.

The art director is responsible for the look of the whole show and, with the art department, decides everything from the colour of the walls to the knick-knacks on a shelf.

The costume designer clothes the actors. My look in the series is different from the pilot because we had a different costume designer who brings her own sensibility.

Neither is 'right' but they are both different and have an impact on what the audience feels about Dirk. Imagine David Tennant's Doctor Who in a bomber jacket and DMs.

The cameraman and the director chose the style of shooting. Again you'll notice a difference between the style of the pilot and the style of the series. Which do you prefer?

Look out for the very first sequence in the first episode of the series, up to the title credits, and imagine quite how many decisions had to be made about a myriad of things just to put that together.

Then there's the music, which has an enormous impact of the feel of a show. Hair and make up, lighting, sound and dozens more, hundreds of decisions have been made about hundreds of things that all impact on what you see on your screens.

Unlike books, which require a writer, a laptop and a reader to do all that work in their heads.

Stephen Mangan plays the title role in Dirk Gently.

Dirk Gently starts on Monday, 5 March at 9pm on BBC Four. For further programme times, please visit the episode guide.

Comments made by writers on the BBC TV blog are their own opinions and not necessarily those of the BBC.