Ernest Nkrumah opens the door of his tiny flat with a blue tooth chip clipped to his chin, and a loud African shirt. His home is rammed with desks, computers and trailing wires. Posters of HIV and Aids line the walls alongside pictures of Barak Obama, Michael Jackson and Ghanaian flags. Nkrumah's humble home on the top floor of a Peckham estate is also his Foundation . His mouthpiece lets him take calls from patients at anytime.
I went to see Nkrumah today for World Aids Day. I came armed with positive facts. The latest UN report  paints an optimistic picture, with new HIV infections at their lowest levels since 1997 across the globe. Meanwhile, the number of people dying from Aids related causes fell from 2.2 million in the mid-2000s to 1.8 million in 2010. It remains terrifyingly prevalent, but the tide is finally turning. We are all learning to address it.
So when Nkrumah started telling me about the devastating discrimination happening on my doorstep, I was shocked.
He spoke about a community where family, friends and faith leaders do not recognise the condition as anything other than a curse. A significant group, who still see HIV as a "dirty illness for dirty people"; a just punishment for inappropriate behaviour. NHS staff are still being refused entry to my local churches to offer tests, and banned from mentioning the disease in front of religious buildings. South London radio stations continue to pump out disrespect for sufferers in different languages, and free contraception is not taken up.
"People are living underground, they do not want to come forward," says Nkrumah, "It's like living below the radar."
These stories are backed up by the numbers. According to the National Aids Trust, some 12 per cent of all HIV sufferers in the country now live in Southwark, Lewisham and Lambeth -- a tiny corner of South East London. The prevalence of diagnosed HIV in my borough more than doubled between 1996 and 2003 , and over 11 people in 1,000 now have it. While the world and the country is making progress, the fight against HIV in parts of our country remains dark, hidden and is getting worse .
These problems persist beneath sterile NHS clinics and rosy-cheeked health workers. Nkrumah told me about finding patients who have haven't been out for years, people whose self esteem has dropped so low they won't even bother taking medication. His self-help groups have to meet in anonymous locations and pretend not to know each other on the street.
Another Aids worker told me about students with the condition being segregated in class. One patient saw a friend delete their number from their mobile in front of their face when they found out. In such a hostile environment, Nkrumah's flat is the only place patients from some communities trust to find understanding.
Although some 50 per cent of the country's HIV patients are now found in London -- largely associated with the relatively high numbers of gay and African men -- other areas suffer pockets of disproportionate prevalence, too. Manchester, Salford, Leicester and Blackpool are some of the urban areas where prevalence persists above the national average.
Any sense that we are disconnected from this problem is an illusion. Most of us won't see or hear about these cases, but they are playing out on our streets. Stigma in any community means people are less likely to be tested, less likely to be treated and more likely to spread the condition. We pick up increased infections and NHS bills. We lose talent from early deaths.
So when news came through today  that there are massive cuts to international Aids funding, we will be the ones who suffer. Over a quarter of my ward are black African or Caribbean, and those that were not born abroad still go back to visit. We cannot afford to be insular on this.
If you're worried that global Aids charities seem too distant and unaccountable, think about visiting Nkrumah and his flat. Read the "thank you" text messages he holds up proudly from patients, and listen to him constantly giving advice through a headset that he rarely switches off. Right now he's struggling to compete with bigger charities for smaller funding pots. If you want to help or need it yourself, think about giving him a call.
Rowenna Davis is a journalist and author of Tangled up in Blue: Blue Labour and the Struggle for Labour's Soul , published by Ruskin Publishing at £8.99. She is also a Labour councillor.