Marcus Mumford looked like a man who’d accidentally stumbled upon music’s holy grail. Appearing amazed he and his band had sold out the Corn Exchange, he gazed the length of the hall and said: “I can see people right to the end! There are an awful lot of people here.”

Get used to it. Rarely have I seen a crowd loving it as they did on Friday night. They knew every word to every song on Mumford & Sons’ debut album Sigh No More and hollered them back at the stage with passion. The way these retro country rockers connected was electric.

The Mumfords marry the West Coast sound of the early 1970s with British indie, but from the spine-tingling four-part vocal harmony that opened the gig (and brought to mind The Eagles’ Seven Bridges Road) it was clear this isn’t simply a good idea whose time has come again. The band makes a beautiful sound.

They are all fine singers and accomplished instrumentalists. Sometimes multi-instrumentalists – Marcus proved he is an impressive, powerhouse drummer.

And while singing of your broken heart in the style of Harvest-era Neil Young ain’t original, they moved it into the present with epic anthem Little Lion Man.

Getting the biggest response of the night, the audience raised the roof when they joined in with the chorus “I really f***** it up this time”. The Mumfords really didn’t.

Neither did opening act Fanfarlo, who seemed to have plugged into the national grid since their Audio gig a month back. They were on fire with a bunch of songs more subtle than the headliners’ but with less stadium potential.