At the same time, the number of bookies' shops in Glasgow leapt a fifth as more Scots became addicted to puggy-style casino machines.
New figures obtained by the Evening Times show there are now 250 betting shops in the city, up from 210 shortly after gaming laws were loosened in 2005.
Campaigners blame the rise on gaming firms expanding in poor areas, where fixed odds betting terminals (FOBT) - now widely dubbed the "crack cocaine of gambling" - are most popular.
Adrian Parkinson, the bookmaker who first brought the machines to Glasgow and now a consultant with anti-FOBT group Fairer Gambling, said: "The fact that you have a 20% uplift in the number of bookies in seven years backs up what we have been saying: bookmakers are targeting certain areas."
Both FOBTs, which offer a variety of old fashioned, puggy-style slot games and casino games like roulette and blackjack, have boomed since Labour liberalised gambling legislation in 2005
The party now regrets this - leader Ed Miliband called for a rethink of the policy last week following grassroots concerns from some of Britain's poorest cities, such as Liverpool.
But it is Glasgow, not Liverpool, where most is wagered on the machines, a total of £1400 in bets per capita were played on FOBTS in the city in 2011-12.
That is more than £800m a year - although money wagered, of course, includes money previously won in play.
The industry response has been expansion, with bookies' shops replacing hairdressers and butchers in high streets and shopping parades in Glasgow's most vulnerable communities.
Currently, each shop is allowed to run four FOBT machines.
Many shops open-up just doors away from payday lenders, cheque-cashing counters and pawn shops - which are also booming thanks to the same relaxation of regulations and the current economic climate.
Local authorities are practically powerless to use licensing or planning laws to restrict such businesses, in the way they can limit the number of off-licences or pubs.
Mr Parkinson added: "The bookmaking sector denies there is any increase in the number of betting shops.
"However, we believe there is an explosion in their number in certain areas - but a decrease in other areas.
"I think what is happening is that bookmakers are coalescing around certain areas that are more profitable in terms of FOBTs and moving out of other areas where FOBTs are not as appealing.
"The truth is, FOBTs do not appeal to somebody who is more affluent."
Glasgow's City Treasurer Paul Rooney is just one of many Labour councillors across the UK who has been lobbying his party - and governments in Holyrood and Westminster - to change course of FOBTs.
Today he said: "The days of all bookies as places full of smoke where guys like Jack and Victor from Still Game put wee bets on horses and football have gone.
"Now, many are empty apart from some guys milling around puggies.
"There hasn't been a 20% rise in the number of bookies because people are queuing out the door to put on their football coupon - it's about getting another 150 high stakes, high-speed gambling machines into the city.
"That is a huge increase in provision we just didn't need."
The Association of British Bookmakers is running a campaign called "Back Your Local Bookie" and still firmly believes in the betting shop as a community hub.
A spokesman said: "Every single betting shop in Glasgow is licensed to be open by the city council.
"Just as is the case with any other retailer, a betting shop will open in response to and meet customer demand, and bookmakers have been trading successfully on the high street for over 50 years.
"Gaming machines themselves have been in shops for 12 years, so are not new products, but they are very popular with our eight million customers"
Across Britain some £1.5bn is being lost every year on FOBTs, which are played by about one in 25 people, said Mr Parkinson.
He said: "That compares with something like £1.2bn lost on the Lottery, which attracts more than half of all UK residents, and an estimated £2bn on online gambling, which is largely based offshore."