Having spent eight years as an NHS physiotherapist specialising in orthopaedics, it's no surprise that Saz Sunthareswaran was keen to start swimming with her baby, Sophia, as soon as she could.

Both mother and baby loved the lessons so much that Ms Sunthareswaran trained as an instructor. Now, just 18 months later, her Oxfordshire Water Babies franchise is doing so well that she has had to take on a full-time administrator and four other teachers.

She said: “Lots of my friends were doing Water Babies classes, so I went along. The classes are really fun; high energy, with lots of mums and babies about the same age.

“It was our highlight of the week. I was thinking of returning to work, but I had been in the NHS for seven or eight years, and it was a difficult time, with all the targets, so I was not enjoying my work so much.

“I thought, at least I would get some fun training as a teacher. Shortly after I qualified, the franchise became available — before that, it had been shared with Berkshire but there were more than 1,000 babies and it was getting too big.

“I took over last November and since then we have doubled our numbers. My husband helps me to run the business, but he still works full-time.

“When I started, I did all the administration myself, but it became a full-time job on its own, with all the clients we have taken on.

“I haven't done any marketing. It's all word-of-mouth — friends recommending friends.”

Babies must start the lessons before they are one, when they lose their diving reflex, which blocks their air passages when they are under water. They progress through different stages until, at the age of two-and-a-half to three, they are ready to join mainstream swimming lessons.

“With our lessons, the mums and the teacher are in the water. There's lots of singing and games, and lots of splashing and noise. It's a big step moving on, when they swim without their mum in the water.”

At first, she did weekend work in the NHS alongside her Water Babies job, but she says the swimming classes are so enjoyable, she isn't sure she'll go back.

“My job is so rewarding. It's making a huge impact on the children's development.”

Her husband Rame, a vascular surgeon, also loves taking Sophia to lessons. Now aged two, she has almost outgrown the Water Babies, swimming a width on her own with only a float for support.

Ms Sunthareswaran said: “Physically, I feel that my daughter is strong for her age group.

“I'm still doing part of the role that I would be doing as a physiotherapist, but it's lots of fun.

“It's very rewarding, seeing what the babies can do in the water. Each time I hear a mum saying: ‘Look at my baby swimming,’ I feel proud.”

o Contact: 01869 325 499, or 07792 899 581 Web: www.waterbabies.co.uk