What do you never leave home without?

Everyone has something without which peace of mind, happiness, or life itself would be unthinkable. On Wednesday, a woman from Kelso, in Scotland, left her hand luggage unattended at Toulouse Airport. She'd just arrived for a two-week holiday with her family in a rented gite. When the security X-ray camera revealed among her underwear, her make-up and her shoes, a small dense rectangular mass which they couldn't identify, they blew up the case.

It turned out to be a packet of frozen pastry. But why, asked a bemused French airport official charged with the duty of comforting the distraught tourist, was she bringing frozen pastry on holiday? They had pastry in France. Indeed, some might suggest that, France being the home of haute cuisine, French patisserie might, in fact, be superior to the cardboard stodge that we this side of the Channel laughingly refer to as pastry.

The tearful tourist explained that it was puff pastry, and that night she intended to make a chicken pie (they always had chicken pie on the first night of their holidays) but without this particular brand of puff pastry the pie, the supper and probably the entire holiday would be a disaster. You see what I mean.

So what item do you value so highly that two weeks without it would reduce you to a quivering neurotic wreck. Books don't count. Everyone takes books on holiday with the possible exception of Michael Owen who, when asked by an interviewer what books he read, replied nervously: "What, you mean all the way through?"

The Hampstead version of that story is the dinner party guest who said he had been on holiday in the Algarve for a fortnight but hadn't managed to finish his book. "Oh dear, what are you reading?" said the woman beside him politely. "Not reading, writing," he replied. I know - I was that woman.

There are exceptions to the holiday book rule. Most people, my family included, grab a couple of paperbacks on their way through the airport departure lounge. The receptionist at the Isle of Eriska hotel overlooking Loch Linnhe told me that every Easter a Canadian couple comes for three weeks preceded by a cabin trunk despatched independently by sea container. It's full of books, she said. They must get through at least a couple of hundred every vacation.

Still in Scotland, but further north, we were staying one summer with friends in Orkney who had had the late American millionaire entrepreneur Armand Hammer, president of Occidental Petroleum, to stay for a weekend. He too was preceded by a great deal of baggage, most of it being crates of bottled water. When asked by his hostess why he had brought so much water he replied that his golden rule for survival - he was 89 - was never ever to drink foreign water. Contaminated water said Mr Hammer was the greatest cause of sickness and death to tourists.

But Scottish water, particularly Orcadian water, is the purest in the world, said his hostess, which is why Highland Park the famous local whisky was so special. "You mean this whisky is made from Scottish water," said the millionaire entrepreneur. "It certainly is," said the lady of the house. "And I'll tell you something else, it tastes a great deal better with ordinary tap water than with that bottled stuff you've brought over from America."

Apart from my Walkman, which I use as other people use reading glasses, my only indispensable prop when travelling is a necklace strung with wooden Liquorice Allsorts. It was made for me by one of my children. It's less a prop than a Talisman, a lucky charm to keep me safe when we're forced to crash land over water and, despite the cabin stewards' safety demonstrations, I've forgotten how to inflate my lifejacket and blow my emergency whistle.

I used to carry a small blue Miraculous Medal given to me by the same Catholic lady who sent me a statuette of the Infant of Prague to guarantee good weather for a family wedding. Unfortunately it went missing and the replacement, advised my Catholic friend, needed to be blessed before it would work properly.

The day before I flew to Italy I bicycled over to the Brompton Oratory to find a priest. Father Pellegrino was in the office they said and so he was - on the telephone ordering wine. I produced my medal and without breaking off his conversation about the merits of De Graf merlot he made a vague sign of the cross over it and waved me away. I reckon my Liquorice Allsorts have the same miraculous properties. I never leave home without them.