Irish singer-songwriter Imelda May admitted feeling perplexed by the invitation to headline the EFG London Jazz Festival. After all, she isn’t currently touring or promoting new material – though she did hint that the “cogs in [her] brain” were whirring with ideas for a new album. Headlining a coveted Saturday night slot – the penultimate night of the festival – at the Royal Festival Hall is no small task. Yet, despite some early sound mixing issues and a couple of false starts, May delivered an incandescent performance, her set richly eclectic and marked by considerable variation in tone, style, and repertoire.

Of course, her rockabilly revivalist signatures (‘Johnny Got a Boom Boom’, ‘Mayhem’) were expected crowd-pleasers. But elsewhere, the dirge-like ballads ’11 Past the Hour’ and ‘Black Tears’ were rendered with arena-rock gravitas, while the jazz-inflected ‘Meet You at the Moon’ – written in memory of her late mother – was exquisitely tender. Tributes to late friends Shane MacGowan (‘A Rainy Night in Soho’, performed with guest Elly O’Keeffe), and Sinéad O’Connor (‘This is to Mother You’), were achingly poignant.

May’s voice is a striking instrument, moving effortlessly between wispy, dulcet tones and raspy, throaty yelps. Her stirring encore of the Shangri-Las’ ‘Remember (Walkin’ in the Sand)’ was unfettered melodrama.