Anyone venturing into the sun last weekend would have witnessed two distinct and bizarre occurrences. Firstly, and most disturbingly, everyone seems to have suddenly become an Arsenal supporter - the red-and-white strip of the double-winning team was all over the capital like a rash. But the second, and more exciting, phenomenon was the re-emergence of wheel power.

London's streets and parks were crammed full of bladers, skateboarders, cyclists and rollerskaters who had opted for an alternative mode of transport to soak up the rays. One confused old lady explained that she took a walk every Sunday and had never seen so many people in Battersea Park: "Is today a holiday?" she enquired.

Like most Londoners, I can recognise a fad when I see one, so decided to beat a path to Slick Willie's to check out the latest equipment.

With so many brands and designs available, the problem for novices is what to buy. You may know nothing about in-line skating, except for the fact that it was pretty unfashionable six months ago, but now, in this heat wave, you simply must have a pair.

"There's been a definite increase in people asking about in-line skates over the past couple of weeks," says Slick Willie's manager, Kem Terani. "Now that we're having more good weather, interest has gone through the roof.

"The store is close to lots of nice parks, so we get quite a few locals coming into the stores for skates, but we get all kinds of people in here. They range from five-year-olds to people in their sixties."

A good pair of in-line skates can cost anything up to pounds 300 - a serious cash outlay to satisfy a summer craving. If you do take the plunge, talk to staff who know the difference between in-lines and quads, and will give you good advice.

Better still, why not rent a pair for a day and see if you survive in one piece? At Slick Willie's, pounds 10 (plus a pounds 100 deposit) will get you a quality pair of in-line skates until 6pm.

In-line skates have been popular for a few summers now, but the re-emergence of skateboarding (since the boom of the early 1980s) has been more dramatic. Skateboarding has always enjoyed cult status, but, for the first time in years, there seem to be dozens of pre-teens cruising down the streets and scraping the skin off their knees trying to perform "olies".

Skateboarding is perfectly suited to urban living. Skilled riders can ride railings and steps as easily as flat pavements, but they are also functional and can be used for something as mundane as popping to the shops for a pint of milk.

Slick Willie's also sell specialist skateboards, but, starting at around pounds 110, they may be too expensive for a novice. However, trucks (the axle that connects the board to the wheels), wheels and decks (the wooden board) are all sold separately and offer excellent quality.

If you just want to cruise around the local park, then you can buy complete skateboards from around pounds 45, but don't be surprised if they show damage after a few serious knocks. A visit to the UK's largest skate shop, Club Blue Room will get you going in the right direction.

Back in Battersea Park, pounds 113 lighter and with a skateboard in tow, I'm wondering if I should have bought a cheaper model.

"Do you know how to olie?" 10-year-old Alex asks me in his brand new "Super Double Gunners" T-shirt. Along with younger brother, Andy, and best friend, Peter, they've had their skateboards for one week. When they discover that I'm still perfecting the "stand-on-board-without-falling" stage they lose interest and disappear.

If I get an Arsenal strip by next week maybe they'll let me join their gang and teach me a few moves.

Low Down: Rent or borrow before you part with your cash. After a few sessions you'll know if you're hooked and be able to have a meaningful conversation with retailers.

There are plenty of purpose-built concrete skate parks that offer the chance to practise harder in-line and boarding manoeuvres. Call your local council for locations.

Slick Willie's: 41 Kensington High Street, W8 (0171-937 3824). Open 7 days, 10am-6.30pm/Sun 12noon-5pm.

Club Blue Room: 141 Park Lane, W1Y (0171-495 5444). Open 7 days, 10am- 6.30pm/Sun 12noon-5pm.