That’s me in the picture: Ros Sare passing the poll tax protest, London, 1990

I was surprised when I saw this photograph in a colour supplement a few days after the demonstration. It was captioned “A West End shopper argues with a protester”, but that’s not what happened at all: I was trying to calm him down. I wrote to tell them truth, and to my astonishment they published my letter.

I wasn’t aware there was a demonstration that day. That morning, my husband and I had been at Heathrow to see our oldest son off on his travels, and to cheer ourselves up I had booked tickets to see Noël And Gertie at the Harold Pinter theatre, just off Haymarket. We got off the tube at Oxford Circus and wandered down Regent Street. It was lovely and sunny. A crowd was marching up Oxford Street with banners objecting to the poll tax. There were babies in pushchairs and dogs on leads – it was a nice, jolly atmosphere.

Suddenly, a line of about 10 riot police with batons and shields came from Piccadilly Circus. They were banging on their shields and chasing these people up Regent Street. It was horrible.

We had got to the Trocadero side of Piccadilly Circus, looking down Haymarket, when I saw the man in the picture – he looked like he could have been one of my sons’ friends. He was absolutely frantic. The police were holding him and I said to him, “For god’s sake, calm down or you’ll get yourself arrested.” I wasn’t concerned about getting involved: I’m not the type to sit back. He said, “They’ve got my girl”, and then I saw this young girl, about 17, being held down by five policemen with her throat against the railings. It was awful. She was squealing.

My husband went straight over and yelled at them, “Let her go. You’re hurting her.”

To our amazement, the police did let her go, and then somehow they let go of the lad, too. The couple were reunited and I said, “Now just run. Get the hell out of here.” And they did.

None of the policemen who had been restraining the girl was wearing an ID number, and my husband asked the sergeant why we couldn’t identify them. He replied, “I know who they are. You don’t need to.”

We then started to go down Haymarket, but the crowd was surging up from Trafalgar Square, and suddenly the police came on horses at a gallop behind the crowd and everybody panicked. It was terrifying. My husband shoved me into a phonebox and we both crammed in while everybody surged around us. People fell over and the horses kept galloping. It was a nasty experience.

We made an official complaint about the whole afternoon, and the treatment of that young girl. About a week later, two plainclothes policeman came to our house to discuss it, and to my eternal shame that’s where it ended. They implied I was being slightly hysterical and persuaded me that I didn’t want anyone to lose their job over the incident. I don’t know what would have happened if we had continued with it, but it’s all history now.

A few years later, this image was used in a media textbook to illustrate how a picture can lie. I look like the typical conservative middle-England Tory voter (which I’m not), objecting to the protest. The truth is, I felt bloody angry that day.