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.
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 Paradise club theme
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.
The Hour's programme theme
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.
The hidden depths to Randall Brown, the new head of news
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.
Freddie Lyons: Bongos and Latin percussion
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.
Bel and Freddie's theme
There is a chiming piano and alto saxophone theme that accompanies her awkward interactions with Freddie - bittersweet and yearning.
Comments made by writers on the BBC TV blog are their own opinions and not necessarily those of the BBC.