News that a Harley Street plastic surgeon has launched plans to sell a controversial anti-ageing drug is greeted with snuffles of derisive laughter in our kitchen.

Jeya Prakash, who says he and his wife have been taking the drug for 18 months, peers grinning out of the paper at her side. He says he is planning to set up a clinic to administer injections of human growth hormone, usually used only to treat dwarfism, because it has made his skin shinier, improved his libido, and had "brilliant" results on Nanthini.

The photo doesn't make them look especially much younger than the 55 and 48 they give as their ages, though, and the remedy, whose potential side-effects are said to include hypertension, carpal tunnel syndrome, fluid retention and diabetes, sounds suspiciously like snake oil to us.

No wonder we've become sceptical. My household's recent experience of Harley Street has left us with the impression that London's medical heartland is teeming with doctors with flashing teeth, giant grins, expensive suits and a super-soothing bedside manner, flogging expensive treatments to the gullible.

We've been taking Grandad, who moved to London to live with us this year, around various specialists shopping for a doctor to look after his assorted ailments. Grandad's a conventional sort of old codger, who thinks you get what you pay for in life, and wants the best medical care he can get - so it was posh Harley Street or nothing as far as he was concerned. But, considering the expertise and expensive care for patients that is supposed to centre on that single North London street, the results have been very odd indeed.

One doctor could talk of nothing but submitting poor old Grandad to a major operation that he didn't want - redoing an op he had a few years ago, fixing some new dodgy bits, adding some electronic bits and generally gingering up his vital organs. "But I'm over 80," Grandad kept pleading; "and my doctor back home told me people over 80 shouldn't have anaesthetics". The Harley Street doctor - whose fees are so high that medical insurance companies swallow and beg not to have to make the payments to him - leaned menacingly over his giant faux-mahogany desk. "If you don't have the operation," he said, his eyes boring into Grandad's like a bird of prey into those of a terrified rabbit, "you will be seriously at risk." "What, dropping off my perch, you mean?" Grandad quavered. The doctor nodded.

The nurse and technicians who were doing tests on Grandad, meanwhile, were saying he looked in pretty good shape. No one could quite understand why the doctor kept sending him off for more tests, which made money for the doctor's friends and scared Grandad stiff, but the results all came back fine.

So it was second opinion time. We were reassured at first by Doctor Two, who said merrily, "so you don't want to have aggressive treatment. And it's true that you'd have a 10 per cent chance of dying on the operating table. Come back and see me in a year." He told us he'd read Grandad's file and knew why all the dozens of medicines he'd been prescribed were needed. But when we asked about Grandad's persistent cough, which had started when a new medicine had been prescribed by Doctor One, Doctor Two only harrumphed. "This is a side-effect of that drug, true," he said, "but you don't want me to change the dosage, do you?" "Yes," we said. "Well, I can't change anything without consulting your previous doctors," he riposted. "I will write to Doctor One and we'll work something out."

We waited. Grandad coughed. The GP was on holiday. Doctor One was on holiday. Doctor Two was unavailable. His secretary said nothing could be done without a letter from Doctor One. After a fortnight or so of increasingly hopeless phone calls, Grandad was sitting up all night coughing his guts up, with only lemon and honey and whiskey to keep him from choking.

Eventually, the other night, Grandad, who'd been talking more and more about how he was at the end of his natural span, croaked miserably, "I think I need to go to hospital tonight. I think I might need oxygen." So off we went to A&E at the Royal Free, where there are none of the grand drapes and copies of Country Life that decorate Harley Street consulting rooms, but it's clean and bright and efficient, with some very drunk patients falling off their trolleys and some very kind orderlies putting them back on.

And, within 24 hours of excellent treatment, the problem was solved. At lunchtime the next day Grandad was sitting up by his bed, doing the Times crossword and chatting with the nurses, as cheerful as anything. He wasn't coughing at all. "The Doctor took me off the medicine and put me on something else," he said happily. "I haven't coughed once since she did."

It was that simple - a bit of intelligent, disinterested NHS care. Despite all the cuts that the Royal Free has been suffering, it can still do better for its patients than the smartest of private care

When we got home, Grandad picked up the paper and started reading about the doctor flogging the secret of eternal youth. We both laughed. "Do you want to try it?" I asked. "No," he said firmly. "I don't ever want to go back there. I don't think we need any more Harley Street syndrome, do you?"

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