By Paul Rincon
BBC News Online science staff, at the BA festival
The number of adult problem gamblers could double or even quadruple when the government's gambling bill comes into force, a leading expert believes.
The bill is supposed to modernise gambling
He says the bill also misses a crucial opportunity to close a loophole which encourages children to start gambling.
Professor Mark Griffiths estimated there were currently between 275,000 and 325,000 problem gamblers in the UK.
The research was presented at the BA's annual Festival of Science, which is taking place this week in Exeter.
Many observers fear that under the gambling bill - which is set to take effect later this year - the UK risks being overrun by Las Vegas-style casinos.
Children 'at risk'
Professor Griffiths also attacked the government's refusal to restrict so-called "amusement with prizes machines", which are aimed at children.
These, Professor Griffiths said, provided a loophole which encouraged children to gamble. "It is a form of gambling, there is no question," he said.
He said the number of adolescents addicted to gambling was about twice the number of adult gamblers. But teenage gamblers, he said, tended not to go on to be adult gamblers.
The government says the bill will modernise gambling, giving the UK's gaming board greater flexibility but also allowing greater enforcement.
But Professor Griffiths, of Nottingham Trent University, who is Europe's only professor of gambling studies, said it would be a "free-for-all".
Nice little earner
"In a betting shop you will now be able to have, say, a roulette machine as well as placing bets," he said.
He thought this would undoubtedly cause a massive rise in the number of problem gamblers, bringing the number to about twice or four times the present figure.
"I have been attacked in the media for suggesting that gambling is a form of addiction. But you see physiological responses with gamblers," he said. "Their adrenalin levels increase."
Gambling restrictions in some countries are thought to have been relaxed progressively because of the tax revenues associated with the activity.