I remember the year I was 18 as being basically one long summer, but the cloying tense sort of summer that makes up coming-of-age novels, and news reports on unusual crimes. It was a weekday, and my boyfriend and I were in the middle of our art-foundation course, and I was worried I might be pregnant. Except, pregnancy tests were £15, and together, we only had a fiver.

On the escalators at Oxford Circus, I'd noticed a series of ads. They were blue, I think, and, in big white letters promised free pregnancy testing and impartial advice. We left college slightly early one afternoon; our journey into town from Chelsea as rush hour built was quietly tense. We stood in a small crush of commuters and all their associated smells and we joked that I should ask somebody to give up their seat. The train was delayed. We stopped joking. We were both aware this was a grownup journey. Perhaps the most grownup journey we'd ever take. On the escalators at Oxford Circus, pen ready, I copied the address from the ads on to my hand, and we skittered to the office, in a pedestrianised street near Leicester Square, bickering. Except, when we arrived, it was closed.

Fifteen years on, I can still remember the hopelessness I felt and the awkward dread I carried with me on the walk back to the station. But today I am also so furiously glad, so impossibly thankful for the problems on the tube. I've thought of that afternoon many times since discovering that those impartial pregnancy tests were advertised by a pro-life organisation, and even more since last week seeing video of the conversations that happened behind that closed door.

The latest investigation into crisis pregnancy centres (the unregulated outlets that promote themselves as confidential advisory services) saw counsellors offering advice that was not advice. It was an anti-abortion banner diluted into speech. It was those photos of bloody foetuses, and the tiny pink dolls women get handed outside abortion clinics, all crammed into soft-spoken lies and a weak cup of tea. They told young women who said they'd just discovered they were pregnant that abortions could lead to "an increased statistical likelihood of child abuse" because women had to break "natural barriers that are around the child that you don't cross" in order to terminate a pregnancy. They said that women who had terminations were 25% less likely to be able to have babies in the future, and discussed "a link with breast cancer". One undercover journalist was told that an abortion carried a number of risks, including "sterility", and that infection was "quite common". "Obviously the instruments that are used are sharp," the counsellor said, "and they can cut the wall of the womb."

The older I get, the angrier I get. By the minute. How dare they subject women – vulnerable, young women, who have gone to these places because they have nowhere else to go – to their dark and prejudiced lies, ones designed to scare them? And at a moment when they're already terrified, too. How dare they call it impartial advice? It's still unclear exactly who funds these clinics, but I know that if they'd advertised as pro-life, I would never have visited. You should know where you're going. What they're selling. They should be forced to state their aims, right there on the door. Laminated.

What would I have done, frightened and 18, with an adult calmly telling me that I might become a child abuser if I had an abortion, and that I'd almost definitely split up with my partner, and that I'd possibly, probably die? Would I have walked out immediately, back into that dusty syrupy heat, and gone over my overdraft in Boots? Or would I have stutteringly nodded along with the adult in charge, and let my life be driven west?

Email Eva at e.wiseman@observer.co.uk or follow her on Twitter @EvaWiseman