The not-for-profit Jazz in Britain team have done UK jazz a huge service by releasing previously unissued material, mainly from radio broadcasts of the time, during what has become known as British jazz's ‘Golden Years’ – the 1950s, 1960s and 1970s. All their releases are limited issues and it is not the company's intention to re-stock titles when sold out – so be warned.

The multi-talented Karl Jenkins’ main orbit was around the bands of Ian Carr's Nucleus and later, Soft Machine. Penumbra II was by a band he briefly led in 1971, made up of an expanded version of Nucleus that Jenkins says performed a limited number of gigs in the first half of 1972, until June when he joined the Softs.

Title track ‘Penumbra II’ is a three part suite that, as Jenkins says in the liner notes, “Could have been written for Nucleus, I guess. My style in that genre – jazz fusion – didn't really change.” And with Carr himself on flugelhorn, this becomes a valuable documentation of a Nucleus that never was, of its time to be sure, but with such an accomplished cast list, the music, especially the extended second movement, is excellent.