The sky darkens above Cable Street in East London, as music student Janée Bennett is en route to a songwriting session with Roll Deep. She’s apprehensive, but she holds her nerve and heads into the studio.

“There were about 15 people in the room and I’d never done a session before,” Bennett tells Music Week. “I wrote a song called Do Me Wrong and I featured on it.”

It sounds simple, but Bennett’s first foray into songwriting came while ...