Distancing yourself and your work from an association with an advert must resemble taking a crowbar to a flashing neon sign attached to your forehead. I get the impression however, that this is less of a problem for Martin Grech. The fragile and unfathomably beautiful 'Open Heart Zoo' may have soundtracked a car advert but the album of the same name which followed in 2002 proved there was much more at work behind the eyes.

'Unholy' follows much the same path as its predecessor. Littered with earthy metal stabs, uneasy cut-up beats and folk asides, it sounds like an aural interpretation of what might emerge if H.R. Giger and Hieronymus Bosch joined palettes. Brooding is not the word - these 'songs' seem utterly detached from the rest of the world. 'Erosion & Regeneration' begins with barely audible cathedral echoes and plaintive piano notes until Grech's unnerving voice begins talking in low, hushed tones. It's minimal to a fault but it's by far one of the most affecting pieces of music here. Previous download-only single 'I Am Chromosome' is a unforgiving clash of grandiose piano and metal thrashing admirable if only for the size of its sound and energy.

The slow build of 'Holy Father Inferior' is another absolute high point - the famous falsetto of 'Open Heart Zoo' makes fleeting appearances on 'Unholy', but when it does it shines amongst its neighbours. Elsewhere, sadly, 'Unholy' remains a mostly challenging and difficult listen. While this is clearly intentional, there just seems to be one too many obvious pitfalls in the process, like a tiringly persistent reliance upon the old quiet/loud formula. The barer folk pieces seem to almost serve as counters to the more atmospherically ambitious tracks, a problem which makes 'Unholy' seem out of focus. This is an album with grand intentions and a clearly talented mind and breathtaking voice at its centre, but digesting and enjoying it will take some serious work.