When you're in the pub or relaxing at home with nicotine-addicted friends or partner, remember their tobacco habit is doing more than just making you cough - it's killing you.

Almost 4,000 people under 65 die each year from lung cancer, heart disease and strokes as a result of passive smoking in their own homes.

And how many of us have worked in a bar, club or restaurant as students to earn some cash?

Did you think at the time, the work was putting your life at risk?

One bartender, waitress or club worker dies in the UK each week because they breathe in other people's cigarette smoke at work. As for other people at work who enjoy a fag break, their second-hand smoke is responsible for 700 deaths a year.

These figures from the Royal College of Physicians make frightening reading.

As a non-smoker, you can try your best to take care of your health but those around you could be sending you into an early grave.

Tobacco smoke contains more than 4,000 chemicals, 60 of which are suspected to cause cancer. It isn't a tasty treat - its ingredients include tar, carbon monoxide and ammonia - and it gets into everyone's lungs.

We have all heard about the dangers of asbestos and seen arsenic used as a murder weapon in movies. In the USA tobacco smoke is in the same cancer-causing category as those two deadly poisons.

The British Government has now announced plans for a ban on smoking in enclosed public places, following in the footsteps of Ireland and Scotland.

Brighton and Hove's Big Smoke Debate survey revealed more than 80 per cent of people want smoking banned in indoor public places in the city.

If you're a smoker, you probably don't want another lecture on the damage it's doing to your health. But we have outlined what it is doing to the health of those around you.

The information and research below comes from sources including the pressure group, Action On Smoking And Health (ASH) and the country's medical advisers, the Scientific Committee on Tobacco and Health (SCOTH) whose report on second-hand smoking produced in April was leaked to the public in October.

Heart disease: Just half an hour's exposure to tobacco smoke can cause the arteries to narrow and reduce blood flow, research has shown. Passive smoking can increase the chances of developing heart disease by a quarter. One study found it could be as much as 60 per cent. A passive smoker's risk of heart disease may be as much as half that of someone smoking 20 cigarettes a day, even though they only inhale one per cent of the smoke. While the risk of lung cancer increases with the number of cigarettes smoked and the duration of smoking, just a small exposure to second-hand smoke can have a large effect on heart disease.

Stroke: Exposure to other people's smoke can increase the chances of a stroke by as much as 82 per cent, one New Zealand study revealed.

Lung Cancer: The risk of developing lung cancer increases by 24 per cent - nearly a quarter - for those who are exposed to passive smoking, according to experts who carried out studies involving women who lived with partners who smoke. Non-smokers exposed to tobacco smoke at work have up to a 19 per cent increased risk of lung cancer.

Other cancers: There is strong evidence that passive smoking increases the risk of nasal sinus cancer and some studies have shown a link between passive smoking and breast cancer and cervical cancer.

Miscarriage: A pregnant woman is more likely to have a miscarriage if her partner smokes heavily during her pregnancy. Researchers found nearly a third of women whose partners smoked more than 20 cigarettes a day lost their baby within six weeks of conceiving, compared to only a fifth whose partners did not smoke.

Asthma and cystic fibrosis: People who are exposed to other people's tobacco smoke for six or more hours a week are 50 per cent more likely to develop asthma symptoms, breathlessness, coughing and wheezing, according to the Department of Health. Cigarette smoke can start attacks in people who already have asthma and it is the second most common asthma trigger in the workplace. There are 3.5 million asthma sufferers in the UK and up to 80 per cent have troubles due to passive smoking. It can also make cystic fibrosis worse and increase coughing, phlegm, pains in the chest and affect breathing.

Smell: Tobacco smoke lingers on the clothes and hair of non-smokers - something they will notice more when they aren't used to the odour. If you are smoking at home or in a non-smoker's home, the smell will get into sofas, curtains, carpets and bedclothes. If you think hanging out of the window or standing just outside an open door is being courteous, watch which way the wind is blowing - your cigarette smoke will only waft back indoors. Your breath, clothes and hair will smell to non-smokers and kissing will be fairly unpleasant.

General discomfort: At the very least, tobacco smoke can make eyes sting and water and cause headaches, coughing, a sore throat, nausea and dizziness for non-smokers.

Damage to children's health:

Almost half of children in the UK are exposed to passive smoking at home and more than 17,000 children under five are admitted to hospital each year because of the effects of passive smoking.

Children have smaller airways and so breath faster than adults, therefore taking in more harmful chemicals per pound of their weight than an adult would in the same time.

As ASH says, children have no choice as to whether they breathe in other people's smoke. Small children might not be able to leave a smoke-filled room if they want to and babies can't ask so it's up to adults to protect their young lungs, heart and body.

Asthma: Smoking causes asthma attacks and makes asthma worse in children. It puts non-asthmatic children and babies at risk from developing the condition. In the UK, it is estimated between 1,600 and 5,400 new cases of asthma occur every year because parents smoke.

Other breathing and lung problems: Babies whose parents smoke are more likely to be admitted to hospital for bronchitis and pneumonia before they reach the age of one. In households where both parents smoke, children have a 72 per cent increased risk of breathing illnesses. They may suffer more problems of wheezing, breathlessness and phlegm. Babies whose mothers smoked during pregnancy may not have such good working lungs when they grow up.

Mental effects: Passive smoking may affect children's mental development. An American study found problems in reading and reasoning skills among children who were exposed to even low levels of tobacco smoke.

Glue ear: Children exposed to passive smoking are around 30 per cent more likely to develop glue ear which is the most common form of deafness in children.

Premature birth and low weight:

Mothers who smoke during birth risk their baby being born too early or too small. In West Sussex, a quarter of pregnant women who smoke have babies half a pound lighter than mothers who don't smoke. Small babies are more likely to be admitted to the special care unit. Experts have found nicotine reaches an unborn baby's bloodstream within 20 minutes of the mother inhaling from a cigarette.

Cot death: Babies of mothers who smoke are nearly five times at risk of cot death compared to those whose mothers do not smoke.

Sperm damage and physical defects: Smoking during pregnancy appears to increase the chance of cleft lips and palates, according to a study by the British Medical Association. There is evidence smoking damages the DNA in sperm and babies born to smoking fathers are at risk of genetic abnormalities.

Smell: A Canadian study found passive smoking affected a child's sense of smell, reducing their ability to detect a wide variety of odours.

Other effects associated with children exposed to passive smoking: These include childhood meningitis, autism, a reduced level of serum vitamin C, cancers and leukemia, an increased likelihood of smoking-related illnesses such as heart disease later in life and more chance they will take up smoking themselves.