When on July 28, 1973, The Band played the Summer Jam festival at Watkins Glen, New York, on a bill that also included The Grateful Dead and The Allman Brothers, Garth Hudson, if he’d been so inclined, could have looked out from the stage onto a crowed of more than 600,000 – at the time, I think, the largest-ever audience for a rock show.

Last night, in London, at the 100 Club, in the company of Goldrush – the Oxfordshire band who have put on tonight’s show with Loose Records and are also among the organisers of the Truck Festival, at which the keyboard legend recently appeared – Garth, here celebrating his 70th birthday, would have looked out from the stage at a somewhat smaller, but perhaps no less enthusiastic crowd.

The Magic Numbers’ Romeo Stoddart’s onstage when I arrive, playing to a noticeably sparse congregation, and I wince utterly as he closes his set with an unfortunately clunky version of Guy Clark’s “Anyhow, I Love You”.

There’s a bit of a stir not long after Romeo’s departed, when Hudson, white-whiskered and resplendent in a snappy Stetson and Los Lobos tour jacket, makes his way through a by-now healthy turn-out, with his wife, Maud, whose wheelchair he guides through the crowd and onto the stage, Maud looking no less natty in a hat as cool as the one Dylan sported on the cover of Desire.

They’re joined by Goldrush, whose playing over the next couple of hours makes you wonder if they have done anything else in what appears to be their relatively young lives apart from listening to The Band, and groups like them. They certainly make all the right noises on an opening quartet of songs that features surprisingly authentic versions of “It Makes No Difference” and “The Shape I’m In” from The Band’s illustrious back catalogue.

Later, there are great takes on other Band classics, among them “King Harvest”, “Ophelia” and, inevitably, “The Weight” and “Chest Fever”, and it’s a testament to the sturdy brilliance of these songs that they sound even in this odd setting so enduringly potent and wholly stirring.

More unexpected, and wholly spellbinding, is a version, sung quite brilliantly by Maud, of one of Bob Dylan’s greatest songs, “Blind Willie McTell”, which reduces the house to a dazzled hush. There’s quickly an outing for “You Ain’t Goin’ Nowhere”, which lifts the evening’s mood to boisterous new levels, almost as many people now onstage, including a horn section who’ve breezed in from somewhere, as there were watching Romeo earlier on, and even more people for the gig’s climax, a roaring version of “I Shall Be Released”.

Garth and Maud are by the end visibly moved by the whole event and the uncomplicated affection of the people here whose lives his music has lit up down the years.

Happy birthday, man.