Richard Lutz watches a whirlwind of music that still refuses to stand still.

Two decades ago, Shetland fiddler Aly Bain says, he was in a pub when he thought it would be great if all his musical pals could sit down and play on a TV show. They would get the best musicians in Ireland and Scotland and blend them with visiting American musicians.

Today, 21 years later, Transatlantic Sessions is not so much a tour but an industry. The format still works and can fill a grand old place like Birmingham’s Symphony Hall.

On stage were no less than 16 musicians and singers: there were aforesaid fiddlers, guitarists, a flautist, a piper, a dobro player and drummers. Bain, who was front and centre, would have been proud. A dream has sprayed lovely music all over the world.

Rhiannon Giddens

The rising star of the big band was Appalachian singer Rhiannon Giddens, with a big, big voice and a lot of stage craft. She delivers a diverse range of songs, about slavery (she herself is Afro-American), to a gospel number from Odetta’s songbook and then, to show real diversity, a plaintive Patsy Cline number about…what else…losing her man.

Irish singer Cara Dillon and Karen Matheson from Scots group Caipercailiie added their voices to what was an encyclopaedia of sound highlighting the tight links between Northern British folk music with its reels and rounds and jigs  to American mountain music to flat-out C&W to rock and roll.

And to display their versatility and need to change, there was music from Pink Floyd to David Bowie to pay credence to songs that can still resonate when a dobro, a pipe or an accordion is added.

Their UK tour continues well into the winter. And no doubt will change, transform and tour again into its third decade with wry Aly Bain and his accordionist pal  Phil Cunningham still in charge ever since that fateful pint in a pub 21 years ago when they mapped out their dream.