It is about five minutes into “The Frame” before Terry Reid arrives onstage at the Jazz Café. As his scratch band lock into limpid funk that sounds like it could go on forever (and very nearly does), Reid comes grooving down the staircase, an odd but endearing mix of West Coast rock gentry and bumbling shires uncle.

Eventually, he makes his way to the microphone and reveals, wonderfully, that the superlungs are still in pretty potent working order. There’s a little more gravel in there, and the empathetic backup of BJ Cole on steel helps fill in on some of the higher ranges. Nevertheless, here is one of British rock’s great voices, in startling form.

It might be better, actually, to talk of Reid tonight as being one of British soul and British country’s great voices, since it is those musical influences that figure strongest in a two-hour set of free-flowing expansions and frequent peaks. A good chunk of the songs come from 1976’s “Seed Of Memory”, the best to showcase Reid’s passionate, improvising grasp of American music. These are loose songs, which he stretches into new shapes with every minute that passes: a clutch of new tunes often begin tentatively, with a kind of country orthodoxy, before being blown apart by Reid’s questing spirit.

During a momentous version of “River”, he generously cedes the spotlight to his band (sharp after, by all accounts, one rehearsal, if generally more comfortable in funk mode) as they take hefty solos: a miracle of abstraction and control from Cole; a slightly hairy burst of session-man technoflash from the guitarist. Some 15 or 20 minutes in, though, Reid finds himself extemporising, a cappella, fearlessly exposed, and the thought occurs that it’s a travesty this free-flying master isn’t as revered as a contemporary kindred spirit, Van Morrison.

Morrison, actually, is one of the very few artists of a certain stature and vintage that Reid doesn’t namedrop during a series of entertaining anecdotes that turn out to be as wide-ranging and ambulatory as his music. One, preceding a mighty take on “Seed Of Memory” itself, leaves me thinking that the song has been covered by Dr Dre: subsequent internet research suggests a new version is forthcoming featuring a rapper called De Mesa, purportedly an associate of Dre but not someone I’ve ever come across before.

Another rambling yarn starts off about someone plausibly significant called Keith and takes in Don Henley, Joe Walsh and Carl Wilson’s wife in passing, but centres around a meeting between Steve Marriott and The Beach Boys. This is a preface, of sorts, to a solo, Latin-tinged version of Brian Wilson’s “Don’t Worry Baby” that only marginally outstays its welcome. It’s followed by another solo song; a rousing, incantatory “To Be Treated Rite” that’s possibly the highlight of the show.

Reid, though, gives the impression that he has enough songs, stories and energies to keep going all night, and he has one good, self-deprecatory joke left, too. As “Rich Kid Blues” begins with all the thump and gravity of old, he steps up and begins singing “Stairway To Heaven” instead. “Well, it sounds like it,” he smirks. But as tonight’s show proves, Reid is anything but the nearly man of British rock.