Across the capital there is a marked increase in the diagnosis of a range of sexual infections particularly in young people aged 16-24 and among gay men.
Figures for the diagnosis of infections gathered from genito-urinary medicine (GUM) clinics by Public Health England show that while levels of infection are up across the UK it is London that is seeing a particularly steep rise.
The rate of syphilis in London has more than doubled in 5 years, with the biggest increase from 2013 to 2014, the last full year of records. In some boroughs the picture is more concerning with a rise of 140% in Lambeth and a three-fold increase between 2009-14 in Southwark.
Rates remain below the national rate for England of 7.8 cases per 100,000 in a number of outer London boroughs. Bexley, Sutton, and Barking and Dagenham have the lowest rates of diagnosis.
Syphilis is a bacterial infection that if left untreated can cause significant health problems and even death. It can be effectively treated with antibiotics and remains relatively rare. Gonorrhoea is a much more common and has also increased dramatically, rising 47% in 5 years.
Once again it is Lambeth and Southwark that have the highest levels. Rates for the City of London are high, though based upon a small population. Most central areas have a rate well in excess of the London-wide average of 190 cases per 100,000 people. Only 5 London boroughs, Sutton, Harrow, Havering, Bexley and Bromley have rates below the England average of 63 cases per 100,000.
The rate in Southwark went up by 172% between 2009-14, while is Lambeth it rose by more than 200%. Lambeth has the highest rate of gonorrhoea in England.
Gonorrhoea is easily transmitted during sex and many people, particularly women, do not show any symptoms. It is treated with antibiotics, though there is concern about the growing resistance of the infection to some of these drugs.
Public Health England analysis shows that there is some difference in infection rates based upon ethnicity with black people having higher diagnosis rates, particularly those living in deprived urban areas.
There are also variation in the distribution of infections according to sexual orientation and gender. Men having sex with other men accounted for 81% of the cases of syphilis and 52% of the cases of gonorrhoea in England last year. Genital warts and chlamydia are nearly all in heterosexual people while 92% of the diagnoses of genital herpes are in women.
Public Health England says that rates are highest in London as the city is home to core groups of people at risk and there is greater access to clinics providing treatment.
It says the rates in gay men are particularly worrying and may be due to unsafe sex, including the decision not to use a condom by partners believed to be of the same HIV status.