1. Jefferiss Wing, St Mary's Hospital, London W2 1NY and North Thames Regional GU/HIV Audit Group, London, UK
2. North Thames Regional GU/HIV Audit Group, London, and Ambrose King Centre, Royal London Hospital, Whitechapel, London E1 1BB and Ambrose King Centre, Royal London Hospital, Whitechapel, London E1 1BB, UK
3. North Thames Regional GU/HIV Audit Group, London and Patrick Clements Clinic, Central Middlesex Hospital, Second Floor West Wing, Acton Lane, London NW10 7NS, UK
4. North Thames Regional GU/HIV Audit Group, London, UK
5. North Thames Regional GU/HIV Audit Group, London, UK and
6. Department of Sexual Health Medicine, Milne Centre for Sexual Health, Bristol Royal Infirmary, Bristol BS2 8HW, and Department of Genitourinary Medicine, West Middlesex University Hospital, Twickenham Road, Isleworth, Middlesex TW7 6AF, UK