Thomas Attwood doesn't know when he first started pooing blood. What he does know is that by the time he wiped his bottom and found the toilet paper saturated in blood, his bowel cancer had probably been present for several weeks and may well have been preceeded by occasional smears of blood in his stool.
"I never used to look into the toilet after I'd been. And even when I passed this huge amount of blood, I didn't go to the doctor until my brother told me I'd be mad not to get it sorted," says Attwood.
Professor Marc Winslett, a surgeon at London's Royal Free Hospital, says Attwood's reaction is quite normal. "Two thirds of the British population never look at their stool and wouldn't know if they were passing blood. Of those who do see blood, only a quarter see their doctor after the first episode. The commonest reason why they do seek help is because a friend or relative tells them they should. And this reticence leads to an average delay of 13 weeks between the initial symptoms and an individual seeking medical help."
The fact is that most Brits don't like to get too involved with their bottoms. One example: 60% of women over the age of 60 mess themselves at least once in their lives. For many, it becomes a long-standing problem. Yet only 5% ever visit a doctor with the problem. That leaves a huge number of faecally-incontinent women out there grappling with the logistic nightmare of containing the smells and stains of their soiled underwear, without ever mentioning it to their GP.
It all comes down to embarrassment, and embarrassment can stop us mentioning a whole range of potentially dangerous yet treatable symptoms. It can also mean we go to extraordinary lengths to disguise the real nature of our problems. A common cause of infertility, for example - and one that may only be discovered after blood tests, semen analysis and sometimes even IVF treatment - is that a couple has never had sex. There are people out there who find it either culturally or personally too excruciating to tell a doctor that their sex life is in trouble. It can be easier to medicalise the problem by complaining of infertility. Doctors are supposed to ask how often the couple has sex, and whether they manage it during the woman's fertile period. But doctors don't always ask, don't always listen, and don't always get a truthful answer. Presumably, doctors get embarrassed too.
Bottoms, sex, vaginas - especially dry, smelly or discharging ones, and bent penises, are all potentially embarrassing because we're brought up not to expose these parts to strangers. Some problems are embarrassing because we worry that they show us in a bad light. Bad breath, smelly feet, sweaty armpits or BO may suggest that our personal hygiene is not up to much.
Some problems are embarrassing because they seem trivial and we're brainwashed into thinking that we mustn't waste the doctors' time. Nails that break easily, hair that's thinning so that you can see bits of scalp shining through, and little crops of spots on your forehead can all ruin the way you feel about your looks but can be hard to broach with any confidence.
Winslett says that the main reason that people delay seeing their doctor is because they're terrified they may have cancer and adopt an ostrich-like defence of pretending it never happened. Cancer phobia may explain reluctance to seek help when you poo, wee or cough up blood or find a lump in your testicle or breast. But it doesn't explain why so many people suffering from depression, sexual problems or alcohol and drugs dependence also tend to wait until a crisis pushes them into the arms of health professionals.
Winslett thinks it's a class thing: "Take the man who bleeds from his bottom. If he's from social class one, he's three times more likely to discuss it with a doctor than if he's from social class four or five."
Now why should that be? You don't need to be a high court judge to tell your GP you just saw blood in the toilet. You don't need to know any medicine or be au fait with fancy Greek or Latin names for bits of the body or their functions to be able to describe what's in the lav. In fact, a GP's life is made easier if people just describe clearly what they have experienced, without necessarily speculating on the probable cause and optimum treatment.
But it's about confidence. The chap from social class one believes his lines of communication with his GP are open. He can say anything; the doctor's job is to listen and take him seriously as he is taken seriously in his own line of work. And it is also a learned behaviour. If you have been brought up believing that you only go to the doctor when you are dying, you're ashamed to be "bothering" the doctor.
The more you use the system, the more comfortable you feel presenting a new problem. Women usually find it easier to talk about sexual problems such as painful sex after they've given birth than before; no questions or examinations are going to be more intrusive than childbirth.
Adolescents are uniquely embarrassed. They usually have little or no experience of the medical system. They often barely talk to their parents, let alone a total stranger. The GP is usually their family doctor and however much the doctor protests about confidentiality, can a teenager really trust the doctor not to spill the beans about drug dependency or an alcohol problem? Adolescents hate to expose their vulnerability; it takes the confidence of maturity to let yourself cry in the GP's surgery as you describe how depressed and desperate you feel. It takes huge skill to listen well to adolescents, and most doctors don't have a single talk on the subject, let alone proper training.
Clearly there should be no health concern that is too embarrassing to mention to a doctor or nurse. It's true that many problems will have no recognised cause or cure but if it worries you, it's valid to seek help for it. The real lesson to be learned is that embarrassment often dissolves - and anxiety withers - just as soon as the words are out of your mouth.
· Dr Ann Robinson is the author of the Which? Guide to Personal Health, published this week, priced £10.99.