I don’t want to simplify a harrowing business. But when, in the middle of this concert with his Spatial AKA Orchestra, Jerry Dammers has a go at “Ghost Town”, the idea that this man would ever rejoin The Specials seems, frankly, insane.

I don’t want to simplify a harrowing business. But when, in the middle of this concert with his Spatial AKA Orchestra, Jerry Dammers has a go at “Ghost Town”, the idea that this man would ever rejoin The Specials seems, frankly, insane.

Tonight, “Ghost Town” begins with Dammers gargling the riff, with the forced assistance of the audience. His 19-piece big band, meanwhile, are playing the song like Duke Ellington’s orchestra transported to Studio One. Eventually, one of the vocalists, Anthony Josep, steps up to the mic, then proceeds to chant, Last Poets style, the lyrics of “Nuclear War” by Sun Ra. After five or ten minutes of this, Dammers scuttles offstage and harries another vocalist, Space Ape (best known as Kode 9’s MC), back to the mic.

Returned to his throbbing bank of keyboards, Dammers sets up a menacing synth hum, over which Space Ape solemnly intones the lyrics to “Ghost Town”, until he is overwhelmed by a cacophonous effort from the eight-strong horn section. Not the way, perhaps, that most Specials fans – or indeed, most Specials members – would like to hear the song.

Great, though, and perfectly in tune with the two and a half hour show. This is Cosmic Engineering: A Tribute To Sun Ra And Other Musical Mavericks, and a chance for Dammers, in the wake of The Specials reunion, to show the esoteric path he has travelled on in the years since their split.

Mostly, the crack band of UK jazz illuminati – from veterans like Larry Stabbins (a personal hero, thanks to his involvement alongside the likes of Robert Wyatt and Julie Tippetts on those great early Working Week singles) to new stars like Nathaniel Facey from Empirical – not a band I’ve particularly liked, to be honest, but it’s Facey on sax who takes the best solo of the night, leaping off from the original Pharaoh Sanders riff in Alice Coltrane’s “Journey In Satchidanda”.

There are, though, relatively few solos here and, apart from a rousing jam during another Coltrane tune, “Om Armageddon”, Dammers’ band are more orchestrated than the wild reputation of Sun Ra might suggest. That said, when I saw the Arkestra itself a few years ago, lead at that time by Marshall Allen, they played it pretty straight. And perhaps part of Dammers’ excellent vision is to show how accessible Sun Ra’s music actually is, very much in the Ellington tradition.

He’s also good at showing up some of Sun Ra’s hokeyness. For all of the cosmic implications, the realities of 19 British musicians in tie-dye robes, masks and Egyptian headgear, playing amongst various bits of sci-fi tat, looks sweetly daft rather than unearthly in the flesh. He draws links between Sun Ra and exotica, playing a Martin Denny tune (“Jungle Madness”) to illustrate his point. This is fun music, is the general idea, and the prospect of presenting Dammers as a supernatural magus, as he fumbles with his mic and makes endearing announcements between songs, is touchingly implausible.

Dammers, though, is clearly having a great, if slightly nervous time. His half-hearted attempts to conduct the well-drilled band are pretty unnecessary, but his keyboard playing – from the Louis & Bebe Barron style retro-futurist skronk he unleashes as his band troop into the venue – is terrific. He really comes into his own during “I’ll Wait For You”, a beautiful, ethereal slow blues by Sun Ra, with Dammers on organ sparring gracefully with the excellent pianist, Zoe Rahman and the vocalist, Francine Luce.

There is one more relative lull; the sombre, angry processional of Sun Ra’s “Discipline In Retrospect” which Dammers pointedly suggests expresses his feelings towards his “six former bandmates”. You could also sense an assertion of Dammers’ own independent spirit in the Sun Ra poems recited by himself and Josep, not least when Dammers declaims, ““Abandon them, abandon them.” Josep follows suit: “A man wants to be a natural free, so he can be.”

Not when he’s playing cabaret versions of “Too Much Too Young” he can’t. It’s curious, though, that Dammers finds creative liberation by subtly updating these strange old jazz songs: adding a slithery funk undertow – courtesy of the breaks-fixated drummer, Patrick Illingworth – to “It’s After The End Of The World” and a superb “Soul Vibrations Of Man” (with an eruptive solo from Stabbins); playing a “Bird’s Lament” that’s closer to Mr Scruff’s version than the Moondog original; finding a way through “Journey In Satchinanda” (one of my favourite pieces of music, apropos nothing) without the aid of a harp.

I suppose there’s a slight sadness here, in that Dammers, for whatever reason, has presented so little of his own music over the past two decades or so. In a perfect world, perhaps he’d be playing new songs inspired by Sun Ra, rather than cover versions.

But that seems a petty whinge in the face of such an exultant night of music. By the end, the band have trooped out of the auditorium and are playing “Space Is The Place” by the Barbican’s toilets. Dammers, meanwhile, is on his own, levering great blats of noise out of his console. The Ricoh Arena, you feel, is truly light years away.