With The 456, Frobisher and Ianto all but distant memories (for us in the UK, anyway) the soundtrack to the phenomenally successful Torchwood: Children Of Earth hits the airwaves. Composed by Ben Foster (Doctor Who conductor, fact fans!) and performed by the BBC National Orchestra of Wales, the listener is treated to 70 minutes or so of music from the recent event - but are the sounds as good as the visuals?

Interestingly, there's not one hint of the iconic, yet incredibly simple, theme tune at all. Perhaps they felt it was a little too ‘BBC Three'. What we do get, however, is a fascinating and eerie collection of tracks that aptly demonstrate a composer very much in tune with the onscreen action.

From the get-go we are in no doubt what's going on. Dainty xylophone and harp in The First Sacrifice merge into dissonant sounds with ominous massy brass intonations - a sign of what's to come. We Are Coming and Something's Coming feature foreboding brass and conflicting strings, the very essence of science-fiction music. But far from being predictable and familiar, this is feverish and, like the five episodes, terrifying and unsettling.

But it's not all strings and brass, oh, no! There's a voice too, and what a sound it is. The haunting, yet utterly mesmeric, solo voice comes courtesy of Annalise Whittlesea. This talented singer appears to be the new Melanie Pappenheim (where do they get these names? From a Jane Austen novel?) who performed similar duties on the Torchwood spin-off show, Doctor Who.

The voice appears in Judgement Day, an incredibly cinematic piece with a gorgeous melody accompanied by the shimmering orchestra. It blends into Requiem For The Fallen (again featuring a heart-rendering vocal) which then in turn merges into The Ballad Of Ianto Jones - one of the album's highlights. Though ‘highlights' does not quite do it service or meaning. It's more of a ‘low'light in tone and emotion. Not a tune for those emotionally unstable 'fans' that can't handle drama. The guitar rears its head but rather than chunking out the sound and emphasising action, here it is used with much thought and sensitivity. There's an almost Spaghetti Western-style feel to the six-string as the orchestra and voice roars behind it like an uneasy ocean. A devastatingly beautiful piece of work that transcends those powerful onscreen moments to become a truly awesome aural experience.

This ‘mini-trilogy' of tracks is equalled in brilliance by the music that accompanies those scenes from Day Five. You know, where that guy did that thing.... If the visuals weren't enough to have you grabbing for a hanky, then Ben Foster ensures there's not a dry eye in the house. (There certainly wasn't in mine!) Requisition 31 and He Was A Good Man evoke a disturbingly unpleasant sensation through the doom-laden strings and the discordant sounds which give way to mournful melodies. Not one for the squeamish or sensitive but unequivocally superb nonetheless.

Composer Ben Foster has delivered an outstanding volume of work here, not just extraordinary for its role in complimenting Children Of Earth, but in the fact that it stands alone as a complete listening experience. It's not just a soundtrack, it's an album. An album to savour, an album to put the willies up you whilst also bringing a tear to the eye. Like the series itself, this release is incredibly powerful, gut-wrenchingly moving and a wholly unnerving piece of work.

Torchwood Children Of Earth Soundtrack CD is released on 27 July. MP3 downloads are available now.