When Sam revealed his bald patch to Carla near the end of the last series of Cheers she was shocked and viewers were horrified. So the rumours about his thinning pate were true. He had, all along, been wearing a 'weave.

Weaves, or hairpieces, are ingenious mini-wigs for men made from real or synthetic hair which are glued, taped or actually weaved with silk thread on to the head. The secret of a good weave is in its colour matching and cutting. If these are done well, a weave can go virtually undetected (specialists assure that you can swim, shower and play most sports). Contrary to popular myth, they do not fly off in the wind, and are a huge improvement on the legendary 'strands-scraped over-the-dome look.

Trenco 229 Kensington Church St W8 (071-221 2646) Mon-Sat 10am-6pm By appointment only

Trenco have been supplying men's wigs and hairpieces to companies for the past 25 years and operating as a specialist salon for men for the past three.

Customers can come in for an initial consultation, view the range and have the size of their bald patch assessed. If they decide to choose a weave it can be fitted the same day, though fittings can take up to three hours.

During a fitting hair will be washed, dried and the weave styled and attached. The replacement patches come on either a skin base or a 'west which are then weaved into the existing hair. These range in price from pounds 175-pounds 400. While they have a wide range in stock for men who are in town from abroad and want something straight away, for a perfect colour match, weaves should be made to order. A selection of wigs are also on sale ranging from pounds 10 to pounds 150.

The Belgravia Centre 2-4 Eccleston Street SW1 (071-730 7188) Mon-Sat 9am-6pm/Tues-Thurs closes 8pm Appointments only

This centre provides the latest technology for male hair loss problems. For young men losing their hair, their trichology clinic offers low-power laser treatment to rejuvenate hair growth. Ten sessions cost pounds 350.

For men who have permanently lost areas of hair, 'hair follicle relocation micro-grafts healthy hair follicles from other parts of the head onto bald patches.

Managing Director Michael Harris says that this does not result in the abhorrent style of strand 'plugs, and looks natural. They will recommend a surgeon to you and prices range from pounds 800-pounds 2,000.

Their single-strand hair replacement patches seem to be the most advanced in weave technology. These are small transparent patches with individually implanted strands of hair which look completely natural, even to a barber. Cost: pounds 4 a square centimetre.

Wig Creations 62 Lancaster Mews W2 (071-402 4488) Mon-Fri 9am-5.30pm By appointment only

Wig Creations specialise in film and television work. Recent commissions include Interview With A Vampire, In the Name of the Father, Last of the Mohicans and Much Ado about Nothing. They are also recommended by The Royal Marsden Hospital to chemotherapy patients.

A private service exists to customers, by appointment only, where a consultation, fitting and a piece can be made in three weeks. They can make virtually any kind of hairpiece, from full wigs and toupees to fine, light pieces on lace bases.

Wigs start at pounds 700 and pieces begin at pounds 450. Frenchman Luc Graf runs the business, which was started in 1946. He is charming and helpful - and completely bald.

Media Hair Systems 3 Craven Terrace Lancaster Gate W2 (071-734 3793) Mon-Fri 10am-5pm/Sat 10am-1pm By appointment only

This company sell a top-of-the-range selection of Bergmann hairpieces from Germany. They are light, made from a fine Begalon fibre and are stuck to the scalp with bonding fluid or velcro.

'A hurricane wouldn't blow them off, says Allan Krist, the shop's owner. Consultations are free before pieces are measured, fitted and cut on the head. These pieces can be worn for 6-8 weeks and then need to be brought in for regrooming (pounds 36). Pieces vary in price, but the most expensive goes at pounds 600 plus value-added tax. A selection of toupees are also available. Full wigs can be made to order.

Geoff Wright Hair, Scalp and Skin Consultant, 156 Marylebone Road NW1 (071-486 4871) Mon-Sat 9am-7pm Geoff Wright is a trichologist who offers both French aromatherapy treatments for men who have begun to lose their hair (due to male pattern baldness) and fine hairpieces.

With see-through mono-filament bases, the pieces are attached to the head with either tape or liquid skin. They can be removed daily or worn semi-permanently for six to eight weeks.

While they stock many pieces at the shop, you can have one custom-made to specific requirements with real or synthetic hair. Ready-made pieces cost pounds 240, custom-made about pounds 700.

'We also do skin analysis and skin problems, says Mr Wright. 'Many problems with hair loss start with the skin.

(Photograph omitted)