Mark Forsythe, 45, is a professional dog walker who lives in London and walks up to 18 dogs a day, charging £10 per walk

Describe your typical day

I leave home at 8am, along with my two dogs, and pick up another four for a walk. By 9.30am we're at the park for an hour's walk. There's a gaggle of people who meet up in the morning and we stand around and drink tea; it's a social meeting while the dogs run around. I then drop the dogs home and at 10.45 pick up a second set, which tend to be bigger.

At 12pm we go to a different park and this walk is the most energetic, I march solidly for an hour. At 2pm, I pick up the third round of dogs; they tend to be smaller and it's a quieter walk. I do the last round at 4pm and at 6pm I drop the last dog home. Then I shower and put on entirely different clothes. It's quite a structured day and I like that – it's like having deadlines.

Why did you decide to become a dog walker?

I used to work in IT and I packed it in and took a year off. When my money ran out I had to look for a job. I was in the park a lot with my own dogs and people started to ask me if I would walk their dog. I did it for free at first, until I realised I could make a living. I had 100 flyers printed and put them in vets and pet shops, but 98 per cent of my clients came by word of mouth.

Do you like the job?

I love it. I like dogs and I love walking, because I find it therapeutic. There's a rhythm to walking, you can lose yourself in it and as I walk I daydream and work things through in my head. I spent so many years working with people I didn't like and couldn't get away from; now I have time on my own. I wouldn't go back to IT for anything in the world.

What's the hardest part of the job?

The first thing people say to me is you must pick up a lot of dog poo. But I don't mind that. I've perfected the knack: take a deep breath, try to do it in a single movement, and knot the bag. The real downside is people who don't like dogs; they can be aggressive and even throw stones. The most upsetting thing is when a dog runs out of the park and I have to keep five others secured and safe. One dog ran four miles and was later found at home. Another time a dog threw itself into the canal, a guy on the towpath lowered me in by holding on to my left arm and belt. I pulled a muscle in my back, got a mouthful of dirty water and cut my shirt on some glass. And I got £10 for that!

What advice do you have for budding dog walkers?

Choose your area well and keep it as small as you can – otherwise you'll end up spending half your day driving around picking up dogs. Also research your market, find an area with middle class families with children and dogs, and where both parents work. You also need the right clothing to suit the weather conditions, so paying a little more for good boots is worthwhile.

What skills do you need?

It's a physical job and you must be able to separate dogs if they fight. I look after people's pets and have access to their homes. People think it's easy, but it's not just a walk in the park.