Admit women or we quit, Sting and Stephen Fry tell Garrick

Signatories, who include the singer Sting, actors, theatre producers and musicians, say: ‘Without serious progress being made to finally address this anomaly, we won’t feel able to continue as Garrick members.’ Photograph: Amy Sussman/Getty Images for Women's Cancer Research Fund

The musicians Sting and Mark Knopfler have co-signed a letter with leading theatre producers and actors, warning that they will be obliged to resign their memberships of the men-only Garrick Club if members refuse to approve a decision to admit women in a vote next Tuesday.

The letter, seen by the Guardian, was also signed by the actor Stephen Fry, the West End and Broadway theatre producer Karl Sydow, and Matthew Byam Shaw, an executive producer on The Crown television series and co-founder of Playful West End theatre production company.