Fear of the water is a surprisingly common phobia and every year, hundreds - if not thousands - of people all over the country try to overcome it with swimming lessons at their local pools.
"Most of them," says Dorothy Heron, our teacher at Chelsea Sports Centre, "have been pushed in as children and you've got to get them to relax before you can even start teaching them to swim. One of the hardest is to get them to put their faces in the water."
In fact, we're all very brave when she tells us to breathe out into the water, with our faces submerged - you can tell by the common look of intense concentration combined with panic.
We all have our foibles. One woman will only swim backstroke, another tries to engage Heron in long explanations so she can avoid any actual swimming. The only man in the group, Richard, seems to have less fear of the water than the rest of us, but also less co-ordination and splashes around dramatically, causing massive turbulence. I can only do breaststroke because it means I can keep my face well out of the water. Dorothy kindly compliments me on it, but I explain that if I go even slightly out of my depth, all ability leaves me and I sink like a stone. Not to worry, she promises, she'll have me in the big pool yet. Oh dear.
By the second week, two would-be swimmers have fallen by the wayside and our numbers are reduced to six. Somehow, Heron persuades three of us into the main pool where we cling on to the side for dear life. Just out of depth, we bounce down below the surface of the water. She tries to get us treading water, too, but, given our reluctance to let go of the side, none of us quite manages it. Due mainly to the relief of being back in the children's pool, we learn to float under the water. We even enjoy it.
Within a couple more weeks, Heron has us jumping in at the bottom of the deep end, albeit only from halfway down the steps. Yet there we are not forced to do anything.
Patience is the key, according to Heron. "You just can't push people," she insists. "You have to gain their confidence and then they'll go from strength to strength."
Heron has taught all ages and abilities. When she was in Streatham, she started the Swans Club for the over 65s, who took it terribly seriously and ended up with fistfuls of proficiency certificates. At the other end of the age spectrum, she teaches children, and particularly remembers one young royal who arrived at his first class in trunks covered in badges. Unfortunately, he could barely swim - the badges had been earned by his older brother and he was wearing hand-me-downs.
By week six, we'd become almost blase about dunking ourselves in the deep end. When Heron produced a ring on the end of a long stick it would have been perfect for dolphins to leap through, but what could be its relevance to us?
"I want you to start at the deep end and swim a length along the side. You can stop as many times as you like and, if you need something to grab, I'll pass you the ring."
She wasn't joking. I don't know how, but we did it - most of us without the ring. We were so stunned that, except for the cheering, we were speechless. How did Heron effect such an extraordinary transformation? It certainly can't have had anything to do with us. One thing, though, is clear. Another six weeks of this and she'll be oiling us up for the Channel.
Many local swimming baths offer group courses for adult swimmers and some also have individual tuitionReuse content