Stay in bed, take lots of fluids -- crates of fluid -- and swallow something for the pain. By that stage you will have swallowed everything else.

Whatever you do, avoid excitement. This means burying your TV remote control in the nearest peat bog or, as the traditional remedy advises, putting your boot through the screen as a precautionary measure. Research has shown that exposure to Gary Lineker can be highly dangerous when England look like winning something.

Just remember: this is the South Africa World Cup. As the great Nelson Mandela almost said, it’s a long walk to freedom, but a short walk to the off-licence. Or the travel agent. Some speak highly of Tierra del Fuego.

Others are already speaking of Fabio Capello in a manner that would make Silvio Berlusconi blush. I don’t say that the English football press are mere groupies, but some of last week’s prose could have been mistaken for lewd and libidinous behaviour.

OK, I admit: a perfect record in a qualifying campaign and a copious number of goals scored cannot be quibbled over easily. No one south of the Border is in the least concerned that Capello has put an entire generation of English coaching talent to shame in the process. Quite right, too. England are up there with the near-favourites.

But let us enter a note of what might be called friendly discouragement. Already there is ecstatic chatter -- did I mention lewd? -- of a squad “going all the way”. Within 24 hours of the admirable Croatia result I was reading delirious essays on how Wayne Rooney will “command the world stage”. Metatarsals, I say.

It’s not meant unkindly, or not entirely. The fact is, nevertheless, that selective, collective amnesia has struck early. For some, the campaign is already won, barring the courtesy of allowing 31 other sides a wasted trip to South Africa. Despite every previous bitter experience -- and I speak as one of five million accredited experts on bitter experiences -- the madness has already begun.

Capello can do a lot, has done a lot, but he can do nothing about that. He has confronted some capable opponents in taking England this far, but he has yet to face the full surging power of England’s worst enemy. It’s a country, starts with E, and it’s not Estonia.

The problem has been acknowledged often enough, but always in the aftermath. It claimed an entire golden generation and a fistful of managers, good, bad and indifferent. It operates like a kind of virus against which there is no cordon sanitaire, least of all for the players. Put simply, the needy national mood affects them, and affects them badly.

This England squad, stuffed with fine players, is in essence the group that admitted to being actually afraid to appear at their home stadium barely a year and a half ago. This is the squad whose veteran speciality act shed real tears when he relinquished the armband. Above all, this is the squad for whom the infamous “hurt” began before they were born.

They are not children, of course. They are millionaire professionals accustomed to the intense demands of the Premier and Champions Leagues. They live daily with intense media scrutiny. But history shows that they wilt under public pressure.

The only alternative to fear that their repertoire contains, it seems, is over-confidence. Capello may be the supreme realist, but he cannot cure the inherent flaw of England’s superstars: they expect to get what they want. They are coddled and it makes them petulant. It certainly makes them ill-suited to adversity.

Meanwhile, England expects. It expects the World Cup after 43 years (and still, obsessively, counting). Of the favourites for South Africa, only Spain has a record of underperformance to match the English legacy and the Spaniards, evidence suggests, are over that hump. Anyone who claims that an insidious popular demand does not gnaw at Capello’s players is foolish. Or Steve McClaren.

Such remarks are well-meant, believe it or not. I could survive a while longer if England fail to win the World Cup, but the frenzy already enveloping the squad verges on the neurotic. It is also just a bit tedious. This is how the English story always goes. Henceforth, ceaselessly, gusts of tabloid fantasy will intervene each time Capello attempts to tether his players to reality.

Still, at least the coach does not pretend that his is the finished article. He doesn’t need to be reminded that Croatia, no one’s idea of a good time, rank ninth, meaning nowhere, in the world. Brazil and Spain lead the betting, for obvious reasons. Holland are going well. Germany and Italy, unlike France and Argentina, must remain contenders. And South Africa itself will present unquantifiable challenges.

Were I of a mind I would advise England’s fans to memorise those Michael Winner insurance ads and calm down, dears. That isn’t going to happen. But if, when, it all goes wrong this time a country at fever pitch can blame the English disease. I’ll send a card.