Having formed in the postpunk years, Nine Below Zero have spent three decades playing a sturdy, robust, very British strain of blues from an era when R&B meant Alexis Korner and Dr Feelgood rather than Beyoncé or Rihanna. They are also highly unlikely ever to have existed without the pioneering musical efforts of tonight's legendarily idiosyncratic headliner.
Chuck Berry's influence on rock'n'roll has been acknowledged by everybody from Keith Richards and John Lennon to Brian Wilson, but tonight, the 81-year-old icon has more basic matters on his mind. "It's gonna get warm in here tonight," he cautions, surveying the compact 100 Club's low ceiling and packed clientele. "But let me tell you, I'm gonna rock you!"
Berry was once notorious for playing take-the-money-and-run live shows with hapless local bands he would hire on the day, but thankfully he has mended his ways. Leading a slick group of bluesmen including his son, Chuck Berry Jr, on second guitar, the smirking figure in a US Navy cap and sequinned turquoise blouse gives what amounts to a one-hour crash course in rock'n'roll history.
He is, understandably, a largely static performer nowadays, but Berry remains spectacularly dextrous, firing out the serrated Roll Over Beethoven and 1955 debut single Maybelline as if he wrote them yesterday. The nimble, shifting blues rhythms of You Never Can Tell collapse into themselves, but Berry has his defence prepared: "Look, I'm 81 years old, and you can't top that!"
Responding to audience entreaties, he even revisits his lewd nursery rhyme 1972 No 1 My Ding-a-Ling, punctuating its Carry On-style innuendo with lascivious, throaty chuckles. His days of doing the Duckwalk may be well behind him, but Chuck Berry remains a compelling, bona fide, rock'n'roll original.
· At Camp Bestival, Lulworth Castle, Dorset on July 18. Box office: 0844 888 4410.