According to new figures collected by the Health Protection Agency (HPA), almost half a million new cases of STIs were diagnosed in the UK last year – and according to the agency, gay men are among the most worrying groups.

Dr Gwenda Hughes, Head of the HPA’S STI department said: “These latest figures show that poor sexual health is a serious problem among the UK’s young adults and men who have sex with men.”

For the first time, the HPA has released figures on which cities and regions have the highest rates of STIs. London features heavily, while Brighton and Hove and Manchester, the three UK cities with the biggest gay populations, come in 10th and 13th respectively.

According to the HPA, some of the more wealthier areas listed may also have higher concentrations of gay men, thereby pushing up the number of STI diagnoses for that area.

Some 482,696 cases were reported in sexual health clinics in 2009, up almost 12,000 on the previous year.