A point of etiquette: just how should one refer to a band with a name which seems to expand and contract in relation to its fluid membership? A Silver Mt Zion started out modestly enough in the late 1990s as an offshoot of enigmatic and influential post-rockers Godspeed You! Black Emperor but within the space of a few albums had expanded to become Thee Silver Mt Zion Memorial Orchestra & Tra-La-La Band With Choir.

Since three of their members left in 2008, they have dieted back down to Thee Silver Mt Zion Memorial Orchestra (or SMZ if life is really too short), comprising the founding trio of guitarist Efrim Menuck, violinist Sophie Trudeau and bassist Thierry Amar, plus Jessica Moss and David Payant, who are all given to performing live in a hermetic semi-circle formation.

Their latest album, Fuck Off Get Free We Pour Light On Everything, continues a predilection for snappy titles which began with debut He Has Left Us Alone But Shafts Of Light Sometimes Grace The Corner Of Our Rooms. But far from being a nebulous introverted workout, the new material is more punkily cathartic and politically engaged (and enraged) than ever. ‘Take Away These Early Grave Blues’ samples the late, great Poly Styrene and elsewhere the album is characterised by ragged, massed onslaughts of lusty fury. Menuck has always preferred punk to post-rock. Now you can really hear that distinction in his music.

Òran Mór, Glasgow, Tue 25 Feb.