She might address love and pansexuality, winning over an unlikely set of listeners on Radio 4’s Women’s Hour but Angel Haze is a more than a little bit scary. The contrast between her composure and the punk singer roar that she channels into rap makes her a captivating live act. It’s a ferocity that was sadly put into soft-focus on ‘Battle Cry’ and her debut album Dirty Gold, probably because ferocity does not sell as many records, but which remains undiminished live.

A tiny, skinny woman of 22, swamped by her rings and bangles and bouncing curls, it’s astounding when Haze picks up the microphone and dives into the first song with all the aggression of the male counterparts she name-checks on ‘New York’ and all the glamour of Beyoncé, whose ‘Drunk In Love’ she covers. In the hands of Haze and guest vocalist Memphis girl Lolo, a woman with a voice so expansive it must have once filled a Baptist church, and a tone that sounds honed by Marlboro Reds, the track becomes an ode to female friendship. Together, with Lolo’s arms spread wide as though funnelling her voice into the room and Haze crouched over her microphone, they work out a yin/yang of a performance, a collaboration that comes from the same vein as the fraught, honest female bonding that happens in nightclub toilet cubicles.

I miss TLC, Missy Elliot and MC Lyte, the women who took on men, in their music and their careers, as equals. I can’t help but wonder what it’s like to be a little girl and grow up with Nicki Minaj as your sole female rapper on the radio, but then perhaps that’s no longer the case, bearing in mind the adoration Haze’s ‘Battle Cry’ is receiving. 

While Haze’s lyrical complexity and rapidity, and the pain and hope in her music, touch on the cornerstones of hip hop - on ‘New York’ she raps so fast the words blur, like fast-forwarding a video tape - the rest of the night happens at a different tempo, a decidedly less frenetic one. With Chvrches and then Metronomy, the music changes to the electronic pop staple - gently thudding beats, melodic synths and melancholic vocals - which have made a name for each.   

With a voice like a former choir girl grown tired of clubbing, Lauren Mayberry, Chvrches’ lead singer, carries the band, whose synth-pop, while charming, is fairly similar to quite a lot of other charming synth-pop bands, flavoured with a reflectiveness that borders on twee. Especially coming after Haze, Chvrches’ version of pop feels like a heavily sedated one, neatly complemented by the swivelling laser lights of The Hospital Club. 

Metronomy do their best Robert Palmer impression, decked out in maroon suit jackets and black shirts, which gave a sense of decorum to music that sounds like it was written for a comedown. It’s nice to see the zodiac getting some recognition on ‘I’m Aquarius’, but I’m a Cancer and I guess it’s just not a love match.

The organisers of the Mercury Prize Sessions certainly tapped in on a zeitgeist moment when they created this line up, but it seems an odd choice to open with a fireball performer and close with a band so successful they seem to have stopped pushing their own boundaries. It might have been more interesting to have chosen between Chvrches and Metronomy and found a mystery third act, one who deviated from the synth-pop standard. After the often tense exorcism of demons that Angel Haze does so well live - her accounts of sexual abuse and religious doubt that push Dirty Gold into uncomfortable listening despite its sleek production - the momentum never quite recovers. It's ambitious to choose an opening act so unsettling, but it sets a high standard to follow that is just never quite met.