Mekons | Photo by Chris Sikich | sikichphotography.com

For nearly 40 years Mekons have mixed and matched punk, folk and a British sensibility into a glorious audible potpourri. On Monday, a packed, sweltering Boot & Saddle beheld the magisterial artistry of Mekons for two-plus hours.

Led by safari-ready Jon Langford and the brilliant voice of Sally Timms, the Leeds-born band were full of harmonious and rocking highs. Joking about this being their first Philly sell out and a far cry from a brawl they started with a sound man at Khyber Pass long ago as well as discussing such oddities as watching Bush vs. Gore on the television, Mekons were in great spirits. And they were ready to pull out high kicks during “Heaven and Back” and intricate hand gestures during such songs as “Belly to Belly,” let alone throw done great harmonies and accordion lines throughout the night.

Touring in support of a 2013 documentary about them that finally got a decent release — Revenge of the Mekons, they certainly played with a vengeance. Tearing through two sets and an encore, it is hard to imagine anyone in the sweaty crowd could have been anything short of overjoyed to witness one of music’s finest treasures, live and full of life.