I always knew I had an artistic streak, so I swanned confidently along to Judith Blacklock's Flower School in Knightsbridge to sign up for her course in floral design. My arrangements were sure to be stunners.

I always knew I had an artistic streak, so I swanned confidently along to Judith Blacklock's Flower School in Knightsbridge to sign up for her course in floral design. My arrangements were sure to be stunners.

Blacklock is today's equivalent of Constance Spry, the queen of English flower-arrangers, who for three decades was the dominant influence on floristry and other aspects of English domestic interiors until her death in 1960.

Tucked away in a manicured mews building, just a stone's throw from Harvey Nichols, the Judith Blacklock Flower School offers a variety of courses, from a one-day taster, where you can learn skills such as the art of making hand-tied bouquets, to an intensive, two-week course in the floristry business, for those looking for a career change.

Regiments of impeccably prepared flowers are lined up outside the school, standing strictly to attention in big green buckets of water. They are the most beautiful and colourful blooms I've ever seen. Who can go wrong with raw materials like these? Not I, that's for sure.

I'm greeted by a phalanx of Japanese handmaidens, who I find out later will assist us. They usher me into the temple where Blacklock, the high priestess of flowers, reigns supreme. A mixed bunch of 12 would-be disciples, we gather around the "altar" - a high floral work table, where we've each been assigned a workstation.

We have come from as far afield as Japan and Sunderland. There is a trio of retired air stewardesses, a florist from Japan who does not speak any English, two American women, a few regulars, and me.

Dressed in smart, blue linen aprons emblazoned with the royal-looking Blacklock gold crest, we are given the tools of the trade: Oasis (the special foam into which you stick the stems), a frog (a plastic container that holds the Oasis), sharp scissors, sticky fixing tape and a turntable (an essential piece of equipment when working on designs such as table arrangements).

Judith Blacklock is a short, forceful, no-nonsense sort of woman from the Lake District, with a sensible, down-to-earth approach to her craft. Her teaching centres on the premise that anyone who understands the basic principles and science of flower arranging can succeed.

We are introduced to the elements of design, which include form, texture, colour and space; and the principles of design, which cover contrast, dominance, scale, proportion, balance and rhythm. Crikey, you don't have to be artistic at all, it seems. I begin to muddle up my contrast and my proportion and get hot under the collar.

First of all, we are asked to make a small decoration. Our mentor shows us what we are aiming to create: a small green upright shape with gold twine around it, topped off with ivy leaves framing a stunning, yellow sphinx rose. Several of these, it is suggested, would be ideal for place settings at a dinner party and they would be an essential item in your floral repertoire if you were going to do this professionally.

The flower business in Britain is blooming, worth altogether some £1.45bn a year. We spend an average of £26 per person every year on flowers, which is £6 more than we spent 10 years ago, but we still have some way to go: our design-conscious neighbours in the rest of Western Europe annually spend, on average, more than £100 each.

Oasis, the material which forms the base for all arrangements, must always be soaked in water for just the right amount of time, usually the time it takes to sink to the bottom of a bucket of water, or about 50 seconds. Then, after pinning a bit of bin liner around the bottom of the Oasis to retain the water, we're off. Well everyone else is off. I seem to be all fingers and thumbs. I can't get my large aspidistra leaf to fold neatly around the Oasis and I feel like a clumsy no-hoper, but, eventually, with a little help from teacher, I finish, far behind everyone else.

Next we are to put together a medium-size arrangement, the sort you get in the middle of tables at weddings. We place the foliage first and then build up the arrangement, adding roses, tulips and carnations. You have to keep turning the decoration and work around in a circle so that the form is evenly spaced. Indecisive and inexperienced, I have stuck in and pulled out the stems so often that my Oasis is riddled with small bullet-shaped holes. But eventually I get there and, thank goodness, it's time for lunch.

My biggest challenge is the hand-tied bunch, today's "must have" floral best-seller. Tied in a sort of spiral, it is a triumph of the florist's craft and while the professionals make producing one look like child's play, in reality it is quite tricky. The secret is to layer the blooms through your hand, building up all the time, again in a circular motion.

After five attempts, which leave my blooms just flopping down limply instead of bunching out in a pleasing three-dimensional triangle, my mentor, firm but kind, comes to my rescue.

I learn to relax my hand, while keeping the stems taut and in place. Eventually, I construct what looks like something that could be sold for good money in a shop. Finally, we frame our bunches with big aspidistra leaves and wrap them in cellophane, giving them the professional touch.

Armed with my creations I get a huge morale boost on the way home when I stop off at my local newsagent who assumes they are professionally created and thinks I must have paid a fortune for such beautiful arrangements. I may not be ready to give up my day job just yet, but I've learnt a lot.

For information on courses, contact the Judith Blacklock Flower School, 4/5 Kinnerton Place South, London SW1X 8EH (020-7235 6235; www.judithblacklock.com)