Mr Matthews has a mission: to revive traditional wet-shaving. A thousand aspirants have each paid pounds 35 to learn his secrets. He is master of the ritual of lathering up, using heat and moisturisers. Abroad, he is something of a celebrity. Just back from wet-shaving missions to America, Canada and Hong Kong, he is soon to appear before 50 million viewers on the Regis and Kathy Lee chat show in New York. There, demand for wet-shaving has increased threefold in 18 months.
Trumper's, where Mr Matthews is manager, is like a gentlemen's club with mahogany cubicles; it is 120 years old, and is hung with satirical political cartoons by Rowlandson and Cruikshank.
Shaving has long had an Italian flavour. I half expected men in fedoras with machine-guns to burst in and pump lead into one of the cubicles - a silly fantasy inspired, no doubt, by having taken a coffee in Renzo's Italian cafe on the opposite side of Curzon Street. Its proprietor, Roberto Di Giuseppe, told me: "Why, I started as a lather boy myself. My father is a barber in Clerkenwell, and back in Salerno my grandfather used to practise by shaving pigs' heads. But it was not for me."
On arriving at Trumper's, I found that traditional barbers have lost none of their garrulousness. Had not the Blairs run into some criticism for taking the hairdresser Andre Suard to Denver with them for the four- day G7 summit, at a cost of pounds 2,000? "Why go for a wayward suburban barber instead of Mayfair quality?" sniffed Mr Matthews. "Downing Street has always been associated with gentlemen's barbers, but Mr Blair has not followed the tradition.
Gossip over, I consented to be swathed in a hot, wet towel by Mr Matthews' assistant.
The insidious ardour with which the hot-and-moist lather is visited upon one's stubble is enough to inspire pity for it: it does not stand a chance. After the hot towel comes a badger-hair brush that has been soaking in hot water, with a dab of moisturising shaving cream inserted in it. Then shaving cream is rubbed into the skin by hand, to "knock the resistance" out of the stubble.
A second application with the brush makes the stubble stand up proud - to be scythed down with a razor running with the lie of the stubble, the skin stretched taut between fingers.
No, not an old-fashioned "cut-throat" blade, but a modern, disposable, double-bladed Gillette Sensor with bendy, "responsive" blades. Inserted into a faux-ivory handle is a heavy bolt, to give weight; the instrument is a Trumper speciality.
The difference between shaving like this and my own scratchy, aerosol- foam technique became obvious. Shaving foam contains more air than moisturiser and does not retain heat. The only way I can get a decent shave is to wash my face with soap and hot water three times, then splash hot water over a handful of cold shaving foam before smearing it on and proceeding to scrape. No wonder I have so many grazes and scars. Heat plus moisturiser, and a good, thick lather: that's the secret. Otherwise, Mr Matthews explained, the skin remains brittle and the stubble hard, so that the second blade, instead of cutting the stubble closer and exfoliating dry skin, will tend to graze it.
Final stages are a cold towel and an application of moisturising lotion. "It may seem time-consuming to go through four or five stages," says Mr Matthews, "but each stage takes only 30 seconds or so. You get a really close shave and it leaves the skin without spots, lumps or bumps. Not a great sacrifice in a 24-hour day."
This is, after all, the smart lifestyle decade: the dressing down of the Seventies and Eighties is over. Which makes one wonder whether Mr Matthews had a hot, moisturising hand in sustaining the Tory government for as long as it lasted.
As I left, two bodyguards swept in. Oh, God, I thought, it's going to be fedoras and machine-guns after all. But no; it was Crown Prince Hassan of Jordan arriving for a shave and haircut.
Trumper's, 9 Curzon Street, London W1 (0171-499 1850/2932).