The number of households gambling more than 10 per cent of their weekly income has quadrupled since the introduction of the National Lottery, a new study has found.
Analysis of official data by Paul McKeigue, an epidemiologist at the London School of Hygiene and Tropical Medicine, suggests the weekly draws have prompted a surge in high spending on all forms of gambling.
"The lottery has increased the prevalence of what one might regard as excessive gambling expenditure. Other surveys have shown this is a good indicator of other kinds of problems - what would be defined by psychiatrists as pathological or compulsive gambling," said Dr McKeigue.
The research, published in the journal Addiction, shows the introduction of the lottery was associated with an increase in average household gambling expenditure from Pounds 1.45 to Pounds 3.81 per week.
More significant, however, is the revelation that the proportion of households gambling more than 10 per cent of their total income has risen from 0.4 per cent in 1993-94, the last full year before the lottery was introduced, to 1.7 per cent in 1995-96.
This rise in high expenditure was most pronounced in households with an income of less than Pounds 200 per week, where it increased from 0.6 per cent to 3.2 per cent.
Dr McKeigue's analysis of the family expenditure survey, annually compiled by the Office of National Statistics from 10,000 randomly selected households, is the only longitudinal study of gambling before and after the lottery.
He feared the problem might get worse if the next National Lottery operator introduces forms of gambling via mobile phones, online terminals and the internet.
In the US, state-sponsored lotteries that have introduced online video gambling terminals have been blamed for causing a surge in compulsive gambling.
Paul Bellringer, director of GamCare, a gambling industry-sponsored charity, said: "Three- quarters of the adult population gamble, but by and large the British population keeps its gambling under control."
A spokesman for the National Lottery Commission said games that encouraged people to participate excessively would not be granted licences.