Hot to trot: Mary McCartney captures the grand final outing of the King’s Troop artillery horses

I grew up with the barracks. Every morning at 8.15 you'd see a whole pack of horses and soldiers walking along St John's Wood High Street – the cars behind them waiting until they'd passed. Although it's not really the usual kind of thing you see in central London, it never seemed odd to me, so I became used to seeing – and smelling – horses around the streets.

I still live locally, so when I heard that the barracks was moving to a new home in Woolwich, I wanted to record the event on camera. Everyone was kind of upset about it, though it's good that the horses are getting a nice new home. The barracks had an event called the Last Hurrah on 6 February, the day before the horses left: there was bunting up the High Street, the infant schools all came out – even some pearly kings and queens turned up. It was a really beautiful British moment, and quite emotional. That so many people turned out shows how much people had loved having the horses around; and I have grown up with animals, I think it adds an extra element to a community.

My mum was horse-obsessed. When we were growing up in London, she had a horse, King, who she kept just outside London at a livery stables. But every so often she would drive him into London and have him in the back garden and ride him up and down our street. It makes me smile now, but at the time I thought she was slightly crazy because obviously no one else's mum was doing that. She also had a little Shetland pony which she used to bring inside the house sometimes; if they were small enough, she'd bring them in – she didn't see the difference between having a little horse and a dog in the house.

Horses are proud, powerful animals, but they're caring and loving as well. They seem to like humans and interaction: you can have a real relationship with a horse, a real connection – without having to use words. As a kid, my way of learning to ride was by getting bucked off and walking home, rather than having riding lessons. But they'd never trample over you, always swerving to miss you; they're quite protective, I think.

I originally went to the event because I was interested in the horses. But I was also really impressed with all the camaraderie between the troops as well as the organisation of it all. I'm always interested in what goes on behind the scenes; backstage before performances or events, before fashion shows or on movie sets. And so I went to the barracks during the preparations for the event, and returned on the morning. It felt special to be allowed in.

On the morning of the last ride out, they all lined up in the courtyard, the same as they had done each morning, raised flags, someone blew the trumpet... They'd always be out at the same time every day, and I think that's why I remember it so much from being little – they'd go past as we were going to school, while people were going to work. It was part of our daily routine. Now they've gone, the area looks empty without them. I think they will really be missed.