A doctor has warned of the rise in gonorrhoea cases in South London caused by fewer people wearing condoms.

Improvements in HIV prevention and treatment mean people are more willing to have unprotected sex, said sexual health expert Dr Anatole Menon-Johansson.

In 2020 more than 8,500 people in Lambeth had a Sexually Transmitted Infection (STI) while in neighbouring Southwark, over 6,500 people were infected over the same period.

The shock figures reveal Lambeth and Southwark as having the highest STI rates in England, with people living in the boroughs four times more likely to suffer an STI than on average in the rest of the country.

Dr Menon-Johansson, consultant in sexual and reproductive health and HIV at Guy's and St Thomas' Hospital said: "What's changed recently is more people are less worried about HIV because people on treatment mostly die of old age and not the virus.

"When a person is successfully on treatment they don't pass on the virus. People taking pre-exposure prophylaxis (PrEP) are less worried about HIV [and] don't wear condoms. People not wearing condoms are more likely to catch chlamydia and gonorrhoea and syphilis so you win some, you lose some in this situation.

"HIV is one giant success story and those figures are good. Based on our current trajectory it's going [to] be hard to get to zero by 2030 which is what Sadiq Khan has said he would like to do."

PrEP is a drug people can take before having sex to protect them from getting HIV. Since 2020, the NHS has given it out for free to people who want it and may be at a high risk of contracting the virus. In 2018, London mayor Sadiq Khan signed a pledge to end new HIV infections in the capital by 2030.

Lambeth has the highest number of new HIV infections in England, with 74 people catching the virus in 2020.

In Southwark, 61 people contracted HIV over the same period – the third highest rate in England. Despite this, new HIV infections are dropping in both boroughs, with the number of new cases falling by more than half since 2011 in Southwark.

Since 2016, people in Lambeth, Southwark and Lewisham have been able to notify sexual partners anonymously by text if they've tested positive for an STI. Dr Menon-Johansson said the technology was ensuring more people who have come into contact with an STI were getting tested.

He said: "We've been using SMS and email to alert people at risk and get them into care. You get the diagnosis and get a link to tell partners straight away. It's anonymous so when you click on the message it takes you to a web page. You can tell as many partners as you wish but the message is anonymous. It doesn't identify the clinic. It alerts them of their risk.

"It's the area that's close to my heart because that's the quickest way of getting on top of the epidemics, getting the right people into the service.

"A lot of people don't have symptoms and they unwittingly pass the infection along. The more people that get alerted of their risk and test, the better."