The WHO calculates that one person dies from tobacco-related disease every six seconds or so, equivalent to about 6 million people a year.

London - Children whose mothers smoked in pregnancy have smaller brains and are more anxious and moody than other boys and girls, a study found.

It showed that babies exposed to nicotine and other tobacco chemicals while in still in the womb were more likely to have trouble eating and sleeping years later.

Tests done at between six and eight years old showed they were also more likely to get tired easily, lack energy and generally look unhappy.

Dutch researchers at Erasmus University compared the brains and mental well-being of 113 boys and girls whose mothers had smoked in pregnancy with that of a second group not exposed to smoke while in the womb.

The brains of those born to smokers were five percent smaller on average and the superior frontal cortex, which helps regulate mood was particularly thin.

Although rates are falling, 12 percent of women in England smoke during pregnancy – and in some towns the figure is above 30 percent.

British experts said the study, published in the journal Neuropsycho-pharmacology, underlines that pregnant women should not smoke.

Dr Simon Newell, of the Royal College of Paediatrics and Child Health, said: “More than 5 000 babies are miscarried in the UK each year as a result of smoking while thousands more are born with serious, yet entirely preventable illnesses.” - Daily Mail