Ryan Witchell is a Conservative activist and works in Parliament for a Conservative MP.

One in four people who suffer from HIV do not know they have it.

That’s almost 25,000 people who are at risk of passing on the infection due to ignorance of their condition. In 21st Century Britain, late HIV diagnosis should not be an issue, but it is. Even though we have modern medicine and a multi-billion pound health budget as weapons in our arsenal to tackle the disease, rates of STIs and HIV infection continue to rise.

So why is this the case? There are many contributing factors. These include lack of education, poor access to HIV services, and mental health issues. There is one new factor adding to the challenge. That is the recent phenomenon of ‘chemsex’.

Last week the British Medical Journal designated ‘chemsex’ a public health risk. Dr Richard Ma, from the Royal College of GPs, has called it a “public health timebomb”. So what is chemsex?

Chemsex has become a term to describe sex parties organised on gay hook-up apps. These often last several days, fuelled by the taking of ‘sexy’ drugs such as Mephedrone, Crystal Meph and G (industrial paint stripper). Why ‘sexy’? This term has been coined due to the supposed euphoric high and raising of one’s libido induced through the taking of such substances. The mixture of a heightened sexual drive and lowered inhibitions (often exacerbated through excessive drug use) has created a dangerous cocktail where HIV has been able to thrive and spread. This environment often leads to men choosing not to wear protection; the result of this is catastrophic.

Typically anywhere between five and 30 guys will attend these parties, and it’s not isolated to any particular class or economic group. Indeed, gay men who attend these three-day orgies range from wealthy city professionals to waiters and even doctors. Limited research has been conducted into the popularity of chemsex but 56 Dean St, the Soho-based sexual health clinic, estimates that over 3,000 gay men who partake in chemsex visit the clinic each month. An additional five gay men everyday are being diagnosed with HIV in London.

Let me be clear – I do not believe that men who attend chemsex parties are representative of the gay community as a whole. Only a small minority of MSM (men who have sex with men) attend these parties but the fad is catching on, and fast, and there is an undeniable link between the parties and the spike in infection rates. So where are they taking place? Lambeth, Southwark and Lewisham are ranked as the highest boroughs for rates of acute STIs and HIV infection rates. Lambeth is number one. It’s no coincidence that the majority of chemsex parties are found south of the river.

The rise of social location based apps (or hook-up sites) such as Grindr, Scruff, Hornet and Tinder has created a perfect storm where men are introduced to ‘chems’ (drugs) and ‘chillouts’. A report conducted by the BBC recently revealed that dating apps have caused an explosion in STI diagnoses: Syphillis has increased by 33 per cent and gonorrhea 19 per cent. I am not arguing for one moment that these apps are wholly to cause for this rise – the problem is much wider – but they do play a part in shaping our attitudes and how we approach sex. Attitudes are changing.

Mental health is not a topic often raised when it comes to HIV but it is an issue which has come to the fore over recent months. I recently spoke to a nurse from 56 Dean St who told me that a minority of gay men purposely catch HIV in order to self harm; the Liberal Democrat candidate for Vauxhall, Adrian Hyyrylainen-Trett, spoke bravely on this matter in this years’ election. Adrian explained how he intentionally contracted HIV after developing suicidal feelings following homophobic bullying.

So what is to be done?

Earlier diagnosis. Nearly half of people with HIV in the UK are diagnosed late and shows no sign of decline – last years ‘figures reveal the highest number of diagnoses among gay and bisexual men ever. The longer someone goes without being diagnosed the more likely they are to pass the infection on and need better treatment. This comes at a cost: each new HIV infection is estimated to be between £280,000 and £360,000 in lifetime costs for treatment alone. The Halve It campaign has made some headway into halving those who are diagnosed late. More still needs to be done – however the Government intends to cut funding for HIV services by 50 per cent.

Education, education, education. Although Sex and Relationship Education (SRE) is taught in state schools, they give insufficient emphasis to teaching HIV/AIDS. If we are to instil children with the knowledge they need, at a time when they are becoming sexually aware, then SRE must become a mandatory part of the school curriculum; this has been shown to delay sexual activity and increased the use of contraception.

Pre-exposure prophylaxis. A controversial weapon to battle HIV is currently being explored in the form of PreP (or pre exposure prophylaxis) which involves HIV negative people taking the drug Truvada as method to avoid infection. Research has shown that Truvada is up to 86 per cent effective at reducing onward transmission. Unfortunately, the drug isn’t licensed in the UK on the NHS, even though studies have shown that treatment did not result in people adopting riskier behaviours or reduced condom usage.

HIV is not the death sentence it was 20 years ago. Antiretroviral treatment (AVT) means that, if diagnosed early, you can live to a normal life expectancy. If treatment is adhered to, a person’s viral load can be ‘undetectable’, whichgreatly lowers your chance of passing on the infection.

There is no silver bullet to kill HIV. We have made huge strides over the past 20 years in combating the disease, but the rise of chemsex demonstrates how attitudes and the way we approach sex present new challenges for the modern era.

This week is National HIV Testing Week, an event which aims to increase testing among England’s key populations affected by HIV and improve early diagnosis and treatment of HIV. Its aim is to raise awareness of the benefits of early diagnosis, and it culminates in World AIDS Day on the 1st December. I encourage everyone; gay, straight, bisexual, or trans, to get tested and support the campaign.