On Thursday nights between the hours of 10pm and 1.30am, you will usually find me cruising the streets of Brixton in a van with blacked-out windows.
I'll be parking down side streets and you'll probably see me roll down the windows and pass the occasional package to someone.
The hours are unsociable and I may well look like I'm up to no good - but this is one of the most enriching experiences of my week.
Welcome to the world of Spires - a charity for homeless and disadvantaged people with a dedicated outreach service for street-based sex workers in South London.
On top of running a day centre, twice, often three times a week, Spires sends out a key worker and a volunteer to local red light districts to distribute condoms, offer needle exchange, practical support and befriending - all from our trusty van.
The clients who use the service - named Streetlink - are female and transgender sex workers, and one of my roles as an unpaid volunteer is to offer harm reduction and support in whatever way I am able to.
At a most basic level, this may entail providing contraception, sharing a cigarette or simply listening. We keep records of whom we see on our rounds and make a note of those we don't.
A client may go "missing" because she's in prison. She may have simply moved away or she may be injured or be being kept against her will by a pimp, boyfriend or punter.
Many don't have family or support networks to report their absences, so this is one of the areas where we can step in by taking phone numbers, putting out feelers and gathering information.
Sometimes we'll drive a client to a shelter or out of the borough if, for example, the police have asked for her to be moved for her own safety.
If a client has been a victim of violence we'll ensure she gets medical care, or if she wants some food, a shower, a nap or to learn more about the rehabilitation or educational services available to her from our partner agencies, we'll invite her to visit our day centre in Streatham.
Some of the stories we hear are joyful, such as the client excitedly planning to make a strawberry cheesecake upon her release from prison, and some are downright funny anecdotes about the stranger quirks of regular customers.
Some are harrowing.
The majority of the women struggle with addiction - be it alcohol, drugs or both. Some have mental health problems or medical conditions which need careful maintenance, like HIV.
They may be pregnant, struggling to support their children or be fighting for access to their little ones.
Many are homeless and desperate to get off the street. Spires can help by arranging for temporary shelter accommodation, as well as long-term supported housing. Specialist counselling and contact with rape crisis centres can also be arranged.
As a full-time journalist I'm constantly exposed to the shitty, bleak side of life. As a result, I've learned not to sentimentalise and that certainly benefits me in this role.
Because there is no point in breaking down in tears while a sex worker tells you she has been raped or robbed or both. It doesn't help.
What I can do is empathise. Organise immediate, practical assistance such as food, clothes, medical care or arrange police intervention.
Violence against sex workers is a huge problem and this is exacerbated by the fact that selling sex is, after all, illegal.
The criminal justice system is heavily skewed in favour of the punter and therefore there is a very real fear of legal repercussions for those sex-workers who wish to and should report violence committed against them.
For these reasons I am personally all for bringing the so-called Nordic model to the UK, an approach to prostitution pioneered in Sweden which effectively criminalises the punter and decriminalises the sex worker.
I'm aware of the debates and the implication that it has simply pushed commercial sex further underground, but from where I am standing it is a system which puts the needs and welfare of sex workers first. And that is where I am coming from.
There is no "saving" in this work, but at Spires we do all we can to support the client's basic needs, link them to local services and promote choice and empowerment.
The day centre offers a wide range of adult learning drop-in classes, including courses in music, budgeting and financial management, citizenship and ESOL and digital English.
If we can assist them in finding an alternative to sex work, then all the better.
I have been asked why I sacrifice a night from an already hectic week to sit in dark alleyways and risk becoming engaged in situations which could turn violent.
On a practical level, I live in the area and I see the girls around. I know where they hang out and it definitely helps that they have come to recognise my face as someone they can trust.
Going deeper, I'm not in any 12-step programmes but I strongly believe in giving service. It is by no means a beatific imparting of moral wisdom - frankly that's the last thing you can expect from me. And it's not a shortcut to feeling better about myself either.
On the contrary, it's a reminder that life is unfair and cruel and at times even more so if you are already vulnerable and/ or being exploited.
It reminds me that there are people out there who will stop at nothing to take what little you have and that the "authorities" will not always be on your side.
But it also shows me that lending whatever little time and skill you have can make a difference to someone else's circumstances.
And that is reason enough for me.
These are women often living violent, vulnerable lives on the fringes of a society that doesn't do quite enough for them.
Spires puts them first and that is why I am happy and proud to donate my time and resources to contribute to that.
What's more, doing so enriches my life too. Of that there is no doubt.
If you would like to donate, money, clothes, food, bedding, toiletries or learn more about volunteering with Spires, visit the website or call 0208 696 0943.