How to make your child's brain bigger

'Cucumber cures scurvy,' says Jackson, four, chewing thoughtfully. 'Oxbridge material, that one,' says Rufus Gordon-Dean, 33, above left, a handsome former Household Cavalry officer and one half of Tarka London, a new company that pledges to turn your dribbling toddler into the sort of child prodigy who gets a starred first in classics aged 11. How? They offer exercise classes - personal training for children, if you like - for children from two-and-a-half to six, specifically designed to 'maximise development while growing their concentration, coordination and communication skills'.

On the face of it, this doesn't look terribly hi-tech. One Tuesday lunchtime, 10 children gather in the hall of Saint Francis of Assisi Primary School in Notting Hill and settle down, sort of, to eat their packed lunches before an hour of activity. Jackson is eating his cucumber pieces; a girl called Martha in a checked art smock is working her way through a packet of apple crisps; a boy named Thomas is jumping up and down, having crammed eight segments of tangerine into his mouth. 'Sometimes the packed lunches have quail's eggs and smoked salmon,' says Oliver Holcroft, 31, Tarka's other handsome co-founder, a former Grenadier Guard (and brother of the actor Edward Holcroft). The pair met in the Army, so they both dig physical activity.

Then it's time for the class: several different games spanning an hour, all designed to challenge these small but powerful brains. Because, according to handsome Oli and Rufus (did I mention they are handsome?) and an increasing number of scientists, children aged between two and six need much more physical activity for their long-term brain development than most currently get. 'People are slowly catching on to the idea that children shouldn't just be in a classroom; that actual physical interaction and learning things with their hands is far more beneficial for their long-term development than making a four-year-old spell and count,' says Oli, who adds that Ofsted currently mandates a paltry 45 minutes of 'vigorous exercise' a week.

They're like dry sponges, these young brains, eager to soak up new information and making between 700 and 1,000 new neural connections every second. I don't actually know how many neural connections grown-ups make per second - I wasn't fortunate enough to go to Tarka classes when I was little - but 1,000 sounds like a lot. And if you want more science, Tarka's website is full of it: 'Physical activity increases bloodflow to the brain - a 2007 study showed that three months of exercise [can] increase bloodflow to the brain's memory and learning centres by 30 per cent.' Another study of nine-to-10-year-olds showed that fitter children had brains 12 per cent larger than those of their peers.

To encourage this brain development, Oli and Rufus typically use a series of colourful plastic educational tools. First, Rufus lays out yellow, blue, red and green plastic circles in each corner of the hall, telling the children to run to certain colours. This they duly do. 'Now run to the blue circles,' says Rufus as he himself runs to the red circles. Most of them follow Rufus, apart from Jackson, who scampers to the blue circles as instructed. So he'll almost definitely be prime minister in a few years.

Next, they climb over small plastic 'islands' to help with their balance; then Rufus lays out four different circles on the floor and fills them with coloured balls. The children are asked to move the blue balls into the blue circles, the green into the green, and so on, while he times them.

'Do you want some music while you do it?' he asks.

'Can we have "Let It Go"?' asks a girl called Camilla in a penguin jumper. Good to know even child geniuses have their weaknesses.

Wind-down involves lying on the floor in a circle doing breathing exercises before various nannies and parents come to retrieve the children from the hall. Tarka's office is also based there, staffed by Oli, Rufus, two other instructors and a paediatrician.

Currently they look after pupils from nearby schools, including Miss Delaney's and Strawberry Fields, and go to the houses of private clients for one-on-one instruction. 'I can recommend them with complete and utter confidence and pleasure,' says Anya Hindmarch; her offspring 'hero-worshipped' Rufus and Oli. Sienna Miller says likewise. 'They greatly support our children's development,' states Miss Delaney. 'In my opinion, every child should have a Tarka day.' Classes start from £22 per child - but they only look after children aged up to six, so there's no sneaking in if, say, you're 31. Which is a bit sad because, like I said, they're both so very handsome.

Visit tarkalondon.com for more information.