Cigarettes, as we know them today, are full of tobacco which is processed from the fresh leaves of the Nicotiana plant. The process involves the plant being stripped of its leaves, these leaves being dried and cured before being shredded into small pieces. There are many varied ways of consuming tobacco, but smoking a cigarette is regarded as the most popular with more than 5.5 trillion cigarettes produced per annum.

So what do we get from smoking a cigarette? There are many reasons for picking up that first tab, each one is particular to the individual involved. The smoke a cigarette delivers is full of nicotine and produces a mild psychoactive effect.

Within ten seconds of inhaling smoke, the brain feels the effect of the drug. The receptor proteins on the surface of the neurons (nerve cells) bind easily to nicotine. When the nicotine hits the nicotine receptor, the neuron sends nerve impulses to targeted organs and tissues around the body. This process causes the release of neurotransmitters which then produces the effects of nicotine.

Epinephrine, norepinephrine and dopamine are the three main chemicals released when we smoke. Epinephrine and norepinephrine raise both blood pressure and heart rate as well as heightening our sense of awareness and concentration. Dopamine is the chemical that is released which causes the more pleasurable effects of smoking and can dramatically change the mood of the individual.

Over time, a smoker builds up a certain tolerance to nicotine which means (as with most addictive drugs) that more nicotine is needed to reach the same high. This is where the addiction kicks in: to feel the same level of calmness that the smoker felt before they started smoking, they have to inhale more tobacco smoke a day.

The implications of smoking on the human body are devastating. Heart disease, and lung cancer are the biggest and most common killers. Other problems associated with smoking are arterial disease, mouth cancer and pregnancy related problems.

Lung cancer is the disease of uncontrolled cell growth in the lung. It can lead to a process called metastasis which is the invasion of adjacent tissue beyond the lungs. Lung cancer is the biggest killer of all the cancer family, contributing more than 1.3 million deaths world wide per annum.

There are two main types of lung cancer; Non-small cell lung carcinoma (NSCLC) and small cell lung carcinoma (SCLC). NSCLCs account for approximately three quarters of lung cancer and can stem from three main areas; squamous cell lung carcinoma, adrenocarcinoma and large cell lung carcinoma. The first type starts near the bronchus and is a slower growing form of the disease. Adrenocarcinoma usually originates in the in peripheral lung tissue and is the NSCLC most heavily associated with smoking. Large cell lung carcinoma is a fast growing form of the disease and develops near the surface of the lung.

SCLC is less common than than NSCLC but is a quick killer. The disease starts in the larger airways (the primary and secondary bronchi) and spreads to the rest of the lungs almost immediately. This form of lung cancer is also heavily associated with smoking.

Symptoms of lung cancer include shortness of breath, heavy coughing (often accompanied by coughing up blood) and huge weight loss. There are treatments available, but the patient has to act quick. By spotting the disease at an early stage, doctors have a higher chance of saving the inflicted by either surgery, radiotherapy or chemotherapy. With effective treatment, the five year survival rate is 14%.

Heart disease is another big problem associated with smoking. On its own, and with no other contributing factors, cigarette smoke significantly increases the risk of coronary heart disease. When adding other factors such as obesity, diabetes and/or high blood pressure, the risk escalates even more. The Surgeon General stated that smoking is "the leading preventable cause of disease and deaths in the United States."

Smoking not only increases blood pressure, but it also decreases exercise tolerance, increases the tendency for blood to clot and replaces oxygen with carbon monoxide in the blood. The ultimate effect of this is an added strain on the heart - a problem that worsens the more the individual smokes. As oxygen levels reduce, the heart has to work harder to pump blood around the body which in turn makes heart attacks and strokes more likely.

Although heart disease accounts for approximately 30-40% of the mortality rate, stopping smoking can greatly reduce the likelihood of a tobacco related death. After kicking the habit, the risk of heart disease falls dramatically quicker than the risk of lung cancer. There have been significant reductions in heart problems after just one year of kicking the habit.

In many countries around the world, tobacco smoking is hugely frowned upon. Tobacco advertising has been outlawed in countries across the globe and some even enforce smoking bans in public places.

In Britain, the smoking ban is partly due to the death of TV producer and general showman, Roy Castle. After dying of lung cancer in 1994 having never smoked a single cigarette, his death was blamed on the equally dangerous second-hand smoke.

England joined the league of nations enforcing the ban in 2007, along with many European countries and 50% of America. Currently, Bhutan is the only country in the world to enforce a full ban on smoking. In 2004 a ban was placed on the sale of tobacco products which was followed by a full ban on smoking in public places in 2005.