I am the composer on the second series of The Hour, a drama set in a 1950s BBC newsroom. My job is to create original music to support sections of the programme, hopefully enhancing them.

I was brought on board just as shooting had started, as pre-recorded tracks of some songs of the period were urgently needed for the performers in the Soho nightclub scenes: Never Do A Tango With An Eskimo, Betcha I Getcha and Softly, Softly.

We assembled a six-piece band like what might be heard in a 1950s club at Chestnut Recording Studios, in a small basement in West Kensington, London: sax, trumpet, guitar, bass, drums and me on piano.

Hannah Tointon (Kiki Delaine) came and sang too.

She seemed a bit apprehensive but was really great; she had a lovely feeling for the character and sang in tune, a relief to all concerned. I think the fragility and vulnerability in her voice really added to the story.

I also wrote a couple of original pieces that the band could play in the background to scenes; time and resources were so short, it's usually quicker to write something original than to research and get clearance, approval and arrangements for existing tunes.

The musical style and period is something I am pretty familiar with and it's a favourite of mine; I had just finished a late 50s jazz-type score for We'll Take Manhattan, (which incidentally my pal John McKay wrote about on this blog).

A tricky part was making series two sound like the established, spare landscape of The Hour, but moving it on, making it particular to the new situations and characters and adding my own composer's voice.

Every composer has personal preferences, I suppose - harmonies, intervals, instrumentation, textures.

There were many lively discussions with the directors, editors, producers and executive producers about getting the tone just right, the balance between irony and sincerity, or whether certain scenes needed music at all - and opinions differed greatly.

At one point, I had to bail out of a particularly fraught sound mixing session and just let the team thrash it out.

The hardest part of the job was the time pressure, and as the schedule continued this got tighter. The first episode is invariably the hardest as the tone needs to be established to everyone's satisfaction.

I think this series is more directly emotional than the first.

A big theme is an inability to confront emotional truths, and the score reflects this: more lyrical perhaps, more expressive and thematic, though in a restrained way.

Over the course of the series, I used a range of instruments including piano, various saxophones, acoustic bass, vibraphone, celesta, percussion and drums - and also an amazing cellist (Nicholas Holland).

I've waited all my life for someone to ask me for a big classic news theme and the 'show within the show' finally gave me an opportunity.

For me, it needed to be very 1950s, confident and authoritative.

I based the theme on the well-known phrase "Cometh the hour, cometh the man," and included chiming bells and 'ticking' percussion - as I tried to do throughout the score - to root it to the idea of The Hour.

I wasn't responsible for the title music - I was spared the honour, and the agony, of trying to replace Daniel Giorgetti's great theme - but new situations demanded new material and writing for character is something I particularly enjoy.

Randall Brown, played by Peter Capaldi, is the new head of news and I suppose his music reflects his eccentricity and intellect, also his hidden emotional depths.

It seemed to work well alongside Peter's enigmatic performance. It's on a marimba which is like a big xylophone, with alto sax and acoustic bass.

I began my career as a percussionist in a rock band.

Bongos and Latin percussion, which had featured a little in the music for the first series, seemed ideal for Freddie Lyon (Ben Whishaw) with his Beatnik experiences and the fresh energy he brings to news reporting - we even gave him a little space-age Sputnik sound, like some sort of radio transmission, a sine wave through an echo effect.

The music for the nightclub hostess Kiki DeLaine and her boss Raphael Cilenti (Vincent Riotta) begins like a siren song and gets more obsessive and psychological as the story progresses.

I asked Helen Hamilton from the band Death Rattle to add a vocal to it - her voice has a similar haunting, girlish quality to Kiki's.

Although Bel is a central character, she doesn't often have music of her own; it's usually about the unfamiliar and sleazy surroundings in which she finds herself.

There is a chiming piano and alto saxophone theme that accompanies her awkward interactions with Freddie - bittersweet and yearning.

Kevin Sargent is the composer on The Hour.

The Hour continues on Tuesdays at 9pm on BBC Two and BBC HD. For further programme times, please see the episode guide.

More on The Hour:
Guardian TV & Radio blog: Vicky Frost on The Hour episode by episode
Life Of Wylie: The Hour 2 Q&A transcript
Cultbox: The Hour series 2 episode 2 teasers

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

The Secret of Crickley Hall, adapted from the best-selling novel by James Herbert, is a chilling ghost story that moves between two time frames: 1943 and 2012.

Filming the contemporary set for the BBC One series was straightforward. However, taking that same location back in time by nearly 70 years was more of a challenge for writer and director Joe Ahearne.

Joe worked closely with visual effects supervisor Chris Mortimer and computer graphics supervisor Jonathan Privett, from the London-based post-production house Rushes.

They applied effects after the drama had been filmed to create the illusion of this passage of time, along with several other highly detailed finishing touches.

Here Jonathan explains how the magic of Crickley Hall was enhanced after the actors had all gone home...

Watch the trailer for The Secret Of Crickley Hall.

Jonathan Privett is the computer graphics supervisor on The Secret Of Crickley Hall. Hannah King, who filmed this interview, is a researcher in BBC TV and iPlayer.

The Secret Of Crickley Hall is on BBC One on Sunday, 18 November at 9pm. For further programme times please see the episode guide.

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

If you had been in our office a few months ago you may have been slightly bewildered by the excitement that greeted our postman.

Never before has the delivery of a letter caused such a stir.

The letter he brought was swiftly passed round everyone and drew many admiring glances.

You would think we had never received a letter in a handwritten envelope before, and for most of us in a work capacity these days that is true.

But it wasn't a celebration of days gone by that caused this excitement, but that Sir David Attenborough was the writer.

Sir David Attenborough on the phone, not email, in 1972

Sir David doesn't use email so working with him to develop BBC Four's collection David Attenborough - The Early Years involved the unique experience of receiving his letter at my office desk.

As the editor of BBC Four's Collections it's my role to find hidden gems in the BBC archive.

Programmes contained in these collections are permanently available to watch in full in BBC iPlayer as part of the BBC Four Collections. They never expire.

We've already launched four collections: Army, Talk, All American and London.

With Attenborough's Early Years, you'll see it's not just full length archive programmes, but also letters, internal memos and photographs which make up this unique collection.

So how did I go about selecting what to finally include?

BBC archive programmes are searchable in an online database. You order DVD copies of everything that sounds promising and start viewing.

With a wealth of material to choose from, we arrived at a list of 30 programmes.

They range from 1955 to 1969 and beautifully illustrate Sir David's early career including his first explorations abroad and first time presenting live in a studio.

The earliest programme in the collection is Zoo Quest To West Africa.

It was during the making of this series that David stepped in front of the camera, thus starting a hugely prolific and successful broadcasting career.

It was quite a bumpy start.

As I read in his book Life On Air, David came across a note from a BBC executive at the time who said of him: "David Attenborough is intelligent and promising and may well be producer material, but he is not to be used again as an interviewer. His teeth are too big."

The collection also captures the evolution of natural history programming and filming practices.

These programmes are amongst the first to be predominantly set on location, which was a significant turning point in the filming of animals.

As Sir David explains in a personal introduction that accompanies the programmes, animal programmes used to be entirely filmed in a studio and "consisted of an expert from London Zoo who brought animals from Regent's Park and exhibited them live in the studio, usually on a table covered by a doormat.

"He talked about them while they struggled to escape from the glare of the studio lights, occasionally wet down his front, bit him - or even escaped."

Attitudes to wildlife were so very different in the 50s that the premise of some of the early programmes can seem a little unsettling now.

Once captured, the animals would have to accompany David on his travels, so feeding and caring duties became part of the editorial of the programme.

Creating the collection made me nostalgic for a time I've never experienced.

In the 1950s much of the wildlife of the planet was un-filmed, even unknown. Trips were largely exploratory and communication back to London was via letters and telegrams.

This led to some treacherous journeys, as David recalls in this Zoo Quest For A Dragon clip.

Having received a beautifully written letter from Sir David myself, I decided that the best way to capture these behind-the-scenes trials and tribulations is through his own communications from that time.

And so I went to the BBC Written Archive in Reading, a fascinating place with four and a half miles of shelving containing millions of documents created as part of the BBC's daily operations.

I spent a few days immersed in old production files selecting documents for inclusion in the collection.

I mentioned to the archivists that it was quite ironic sitting here reading letters from Sir David whilst I myself had also received a letter from him.

I made a joke about framing my letter and was swiftly told that any letters David wrote to me are property of the BBC too, and should be handed over to the archive.

So as I wait for my next Attenborough letter to arrive I wonder whether I could still frame it and give the archive a photocopy. Probably not.

Sandra Gorel is the editorial executive for BBC Four Collections.

David Attenborough - The Early Years is available to watch in BBC iPlayer as part of the BBC Four Collections.

Alongside the Collection, Attenborough: 60 Years In The Wild is a three-part series on BBC Two in which Sir David looks back over his career in natural history. Episode one is available in iPlayer until Friday, 7 December.

More on David Attenborough:
About The BBC blog: Marking David Attenborough's 60 years in broadcasting
Guardian interview: David Attenborough: Force Of Nature

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