Star rating: ****

Keeping a large musical ensemble such as The Unusual Suspects alive is a feat in itself. Ensuring that it continues to develop, as evidenced by this latest performance, is deserving of an extra pat on the back, although the Scottish Arts Council's support, duly acknowledged here, is doubtless of more practical value.

David Milligan and Corrina Hewat will celebrate five years of the Suspects when they play at Celtic Connections in January. It's already quite a different beast from the Scottish lion that roared on its debut. It is slimmer, of necessity, and, while still very much founded on traditional music's metres, its ratio of naturally coexisting jazz and folk elements has shifted in the former's favour.

The punch of the brass arrangements here and the go-for-it soloing of trumpeter Colin Steele and tenor saxophonist Konrad Wiszniewski gave the orchestra a tougher edge. Alyn Cosker's arrival on drums, bringing with him the same crispness, drive and big-band awareness that he gives to the Scottish National Jazz Orchestra, also lent increased definition and power.

The centrepiece of this latest foray was the Lorient Suite, which Milligan and Hewat composed for the long-running Interceltique festival in Brittany. Skilfully using all the Suspects' resources, it brooded and danced, the four-piece fiddle section now willowy and smooth, now gutsy and biting, it married strong themes with spontaneous percussion and saxophone tumults.

Elsewhere, the orchestra grooved behind Hewat and piper-whistle player Annie Grace's spirited singing of Jacobite Donald MacGillavry's praises and a brass chorale beautifully topped and tailed Hewat's reading of Time Wears Awa'. Unusual and suspect they may admit to being, but they're taking Scottish music forward with giant steps.