Why was Sophie Rhys-Jones reluctant to have a bodyguard? asks HESTER LACEY. Her head-turning escort was an absolute dream
Until this week, Sophie Rhys-Jones resisted having a personal bodyguard, because she doesn't want to draw attention to herself. Sophie, there's nothing to worry about. Because the one who'll be drawing all the glances probably won't be you. I know because I spent a morning being escorted by Mark Benson, one of the main men at Pantherr Securities, a London firm which specialises in protection, and I barely drew a flicker of interest before the eyes moved on.

The one who makes people look twice (and probably under certain circumstances think twice) is Mark. Discreetly dressed in low-key black, but still, at 6ft 7in and 21 stone, Mark does not look like a man to be trifled with. "In general, in the street, people tend to get out of my way," he says modestly. This is not wholly surprising: in his spare time, he enters strong-man competitions and pulls trucks with his bare hands.

Mark, 25, has been with Pantherr for four years, and this kind of one- to-one low-risk assignment is a pretty easy job. He is more likely to work as part of a team, keeping an eye on clients from rock stars to businessmen (and/or their wives). We set off with me in the back of the car, because the back is safer. "If anyone wanted to shoot you, you've got me in front of you," explained Mark reassuringly. First stop was the Fabulous Fingers nail salon in Clapham. This was the first time anyone had ever turned up for a manicure with a bodyguard in tow and, with Mark looming in the background watching every stroke of the nail file, we received extremely attentive (though giggly) service. Shirley, wielding the nail polish, asked Mark if he'd like anything done to his nails and he blushed. It turned out that he prefers to stay out of the limelight. "I'm quite shy really," he said. "I don't like cameras much."

Next we headed for Asda in Clapham (well, even royal brides need to buy groceries). In an ideal scenario, Mark would park as close as possible to the entrance to any shop and whizz me in at top speed. The most dangerous place for any client is outside on the street or in any open space - shops are a more controlled environment. "If anyone tries to attack you in a shop, I'm going to catch them, no two ways about it," said Mark. Sadly the car was too tall to fit up the ramp to the parking spaces directly in front of the way in; still, we secured our trolley without any mishap and zoomed round the aisles as other shoppers respectfully got out of the way. To avoid smudging my new nails, could I get Mark to carry any bags? Sadly, nope. He has to keep his hands free in case a villain leaps out and needs dealing with.

Then it was time to head for the posh end of town, to meet my glamorous friend Anna for a glass of champagne. One thing is certain, with a bodyguard in tow, Sophie R-J will never have to open another door in her life. Mark not only held them open for me but steered me swiftly through the Oxford Street crowds, a reassuring presence at my left shoulder. Anna was much impressed and we both sniggered foolishly into our champagne flutes as people eyed us surreptitiously. Mark stuck abstemiously to orange juice.

To reach this degree of utter professionalism, he has undergone a lot of training. Initially, he spent hours running through the Scottish mountains, carrying logs through freezing rivers, and being woken up at 3am to do more of the same. And that was just to check that he was of the right temperament - someone who wouldn't go berserk under pressure. He is also a dab hand at restraint and disarming.

This could have come in handy for the next exercise, shopping for clothes, but in the event we were unmolested. Mark was unimpressed with a pink cheesecloth top. "I wouldn't," was his stern verdict. He was more impressed with a silky camisole style. "That's quite nice." Outside the changing rooms, he confided, he usually has only one opinion. "You always have to tell them they look nice," he said diplomatically. And he's not keen on being asked to hold the clothes hangers.

Finally it was time for lunch. Most of Mark's clients don't let him sit at the table with them - he often ends up in a discreet corner, keeping an eye on things from a short distance. Even more likely, once he's got them ensconced at the VIP table, he sits in the car, waiting for the call on his mobile to pick them up. We thought this rather unfair, especially as the car had been left in the dark bowels of Selfridges' car park. So, once our pavement table had been passed as safe, Mark had a steak.

He hardly drinks, doesn't smoke and works out five times a week. At the moment he has as much work as he can handle - 65 to 70 hours a week, mostly at night. Last night he was out till 3am, waiting outside a restaurant for a bunch of businessmen. His girlfriend, who works as a dog-groomer, has had to get used to it, not without some demur (she has their boxer and basset hound for company in the wee small hours).

It's part of Mark's job to know the hottest late-night spots when a client from out of town needs guidance. At the moment, he says, the Mirabel and Titanic are in, plus China White's off Regent Street and old favourites the Ivy and the Groucho. The Atlantic and the Met have slipped from favour. Do clients ever ask for dodgy clubs and naughty things? "They do." And do they get them? "Depends what they're after." Do they ever get blotto and need to be scraped up and carried home? "They know how to party." Some are friendlier than others. "I keep quiet until I'm spoken to. The women are usually more chatty than the men. A lot of them find it a bit of a giggle."

An expensive giggle, at pounds 50 an hour, but worth it, we felt, striding along with Mark in our wake. He is not the largest you can get for your money; his colleague Big John, for example, tips the scales at around 30 stone. These days, however, more clients are going for a low-key approach. "Some people like the great big guys as bodyguards because it draws attention to them, but some don't. I often try to look like someone's husband or son when I'm out with them. Today a lot of people go for the smaller guys, or for women, who don't stick out so much."

Glam friend Anna, much struck with this notion, wondered if she could be a female bodyguard. "I'm very good at kicking people." She would, however, she admitted, draw the line at sustaining any bodily harm in the line of duty. Mark, who was recently threatened with a knife, pointed out that actually, that's what the job is all about.

Pantherr Security: 0171 242 2729.