Women's groups are calling on the organisers of the Rhythm and Vines music festival to drop UK artist Dizzee Rascal over a domestic violence conviction.

The rapper, whose real name is Dylan Mills, received a 12-month restraining order and a curfew this year for assaulting his ex-partner.

An open letter by advocacy group Beneath the Glass Ceiling, which was signed by other groups, said the festival was sending a message that intimate partner violence was not a big deal.

Women's Refuge was one of the groups which signed the letter.

Its chief executive Dr Ang Jury spoke to Māni Dunlop.