There are few greater contradictions than sitting in a London pub in trendy Farringdon and listening to old-style honky-tonk bluegrass performed by four Scottish lads dressed in NME finest. Having survived the experience, I can tell you that expectations notwithstanding, The Dirty Beggars managed to create more atmosphere and more joy in a room of 40 people than I’ve experienced in some arena shows.

Their fairly lengthy show featured an electric combination of original tunes and covers of old bluegrass standards. Their general exuberance never once let up, and infected the crowd, who slowly rose out of their chairs to stomp along like they were keeping time out on the prairie. Without benefit of microphones or amplifiers, the band’s voices rose in perfect harmony and balance with their fine instrumentals. Each player got a chance to show off on instruments and on their vocals, but the show was never better than when they all harmonized together.

What will surely turn out to be a signature tune in their live shows fell strangely flat with this audience: a bluegrass cover of Beyonce Knowles’ 'Halo'. (It should give you an idea of the musical tastes of the audience that I was one of very few who even recognized the song, let alone sang along).

If there is any one criticism of the show, it’s that the lyrics in some of their original tunes are trite – not terrible, but nothing to remember or note in any special way. But lyrics almost seem irrelevant in this genre. Bluegrass is a true musician’s genre; every player has to not only play their complicated parts to perfection, they have to keep time themselves, as the only external rhythm comes from the audience’s stomping feet.

For a final encore, the band called the opening act forward and performed the stage equivalent of a giant campfire sing-a-long, a joyous way to end a joyous show.