In 1985 Derek William Dick, the Scottish singer known as Fish, was locked into an intense, vivid and kaleidoscopic LSD experience which provided him with the inspiration for a concept album Misplaced Childhood, which would go on to be hugely successful and spawn multiple hits. Forty years later, the closest thing to hallucinatory visions tonight are the trippy, lysergic slides that play behind him, as the ex-singer of the neo-prog rock outfit Marillion begins his farewell tour at 66.

There are roars from the crowd and a Scotland flag draped over the balcony to welcome the singer and his band, who prepare to depart on an emotional note. The opening Vigil, from Fish’s 1990 debut solo album, comes to life with atmospheric whirrings of synthesiser that float through the room before Fish’s voice gently joins in, and soft plucks of glimmering guitar arrive as it hums along with an ever-building presence before erupting with euphoric force. It sets the tone for an evening of back and forth between theatrical, epic, sprawling soundscapes and tender, stripped-back, restrained songcraft.

Fish’s voice mirrors this pendulum swing too, sounding mighty, rousing and a little raspy on tracks such as the thundering Credo or the punchy Big Wedge, but graceful and sweet on songs such A Gentleman’s Excuse Me. The band’s playing, if occasionally a little dated and tonally repetitive, is immaculate and slick – as displayed during moments such as the vast six-part song Plague of Ghosts, which is stuffed with intricacies and details. Clearly it’s the stuff prog rock dreams are made of as some fans appear almost hypnotised by it.

But they are soon shaken out of their spell by a rapturously received encore of Marillion hits, Kayleigh, Lavender, and Heart of Lothian, and these power ballads and triumphant pop-rock result in some emphatic singalongs. A closing version of The Company brings it home, by which point big, burly blokes are in floods of tears as Fish finally wraps up his long, winding and colourful trip.