John Legend’s intro music, the 1973 Stevie Wonder track Higher Ground, wasn’t chosen solely for its party-starting funkiness. Its excoriation of politicians could have been written by an increasingly outspoken Legend, who has been scrapping with Donald Trump on Twitter. Having primed us, the singer immediately turns the tables and ripples through a set that highlights artistry rather than activism. Only during the closing moments, navigating the ballad-hymn Glory as footage of protestors plays on a screen, does he return to the subject: “We’re celebrating Dr Martin Luther King and everybody who marched with him.”

The 90 minutes in between – Legend is headlining the opening night of London’s annual BluesFest – highlight the strengths of the neo soul singer-pianist, and a few weaknesses. In the second category, Legend has a tendency to fill the gaps between songs with rote, let’s-love-ourselves exhortations, and lacks the showmanship required for a musician to own a room as big as this one. In the first is his uncontestable talent, displayed in fluid piano runs and a melody-enrobing baritone, which makes him admirably suited to the playing of pensive love numbers such as All of Me and Ordinary People.

Yet when away from the piano, he’s no less sleek and urbane, though he is distinctly warmer and more reachable. During, say, the 1970s-influenced soul-burner Slow Dance, he informs us: “Chrissy [Teigen, his wife] is all the way in Los Angeles, but she gave me permission: who wants to slow dance with me?” The fan awarded the honour is more than equal to the challenge: her confident wriggle-about with Legend is one of the best moments of a mostly likable show.