Fears are growing over the addictive nature of the roulette machines that keep bookies in business these days. Amelia Gentleman visits betting hotspot Slough and watches the punters' £20 notes disappear into them

The biggest spender in Slough's Roar betting shop on a slow Wednesday morning is a middle-aged British Asian man, carrying some belongings in a Sainsbury's plastic bag. He comes in with £180 in his wallet, which he feeds rapidly into the roulette machine and, within the space of around five minutes, loses.

He returns half an hour later with another £160. For a while it looks as if he might be winning back his earlier losses because a lucky spin inflates his first £20 stake to £176 on the screen. But he spins again and the cash drops to £146, jumps to £171, falls to £87, then to £55, and runs out. The machine sucks in a few more twenties, digesting the notes with a satisfying rattle. After a few minutes all the money has gone.

He says "Fuck" but without much anger and takes a chocolate Club bar from a plate on the counter by the cashier's desk. He lifts it questioningly, so the manager can see what he is doing, silently asking for permission to have it. He declines to have his picture taken in case his wife spots it, won't stop to discuss his £340 loss, and leaves the shop eating the biscuit.

At the table in the centre of the shop four older men, all white, mostly retired, observe how much he loses without surprise. "I see him losing all the time. Hundreds," John Mulveny, one of the punters, says. He has a pile of coins in front of him, is studying the racing pages of the Sun, and thinking about where to lay his daily £3 stake. "The people who play the machines have a problem."

Naseem Khan comes in around midday, a half-smoked roll-up stubbed out between his fingers. He seems in a hurry, but takes a moment to inspect the screens of each of the shop's four roulette machines before selecting one in the corner and, hunched over the screen, feeds three £20 notes into the machine in the space of about three minutes. His playing style is relatively slow and cautious. For more aggressive players, the machine's design allows £100 to be staked every 20 seconds.

He is losing to begin with. He mutters and jabs angrily at the machine so that other punters twist their heads to see who is banging on the glass screen. He chews his nails, shakes his head, adjusts his underwear and says "Shit" and "Fuck that, man", but then another spin dispatches a simulated white ball rattling around the wheel and sends the electronic digits on the bottom right of the screen up to £72. He takes a printed-out receipt to the desk and cashes in his winnings. He is £12 up.

"That'll give you some money to buy nappies," Annie Sheffield, the shop's manager says, laughing. She knows her regular customers well and Naseem comes in a few times every day. Last week he announced he had had a baby. He has described himself as a car salesman, but Annie doesn't think he has a job, remarking drily when he has gone: "Unless he works at night, when we're closed." Naseem doesn't laugh at the mention of nappies and rushes to the door. "I'm lucky to get out of here, lucky to get it back," he says, one foot outside the door, anxious not to linger. "You always end up putting it in. It will always take more from you. You never win." He thinks he has probably lost £270 on the machines over the past week.

Feeding the beast: a punter puts a coin in a roulette machine. Photograph: Alamy

Known as the crack cocaine of gambling, these roulette machines have attracted new interest this year after research showed there was a far higher number of the terminals in poor areas of high unemployment than on richer high streets. The Fairer Gambling research showed that in the 50 parliamentary constituencies with the highest numbers of unemployed people, there were 1,251 betting shops, and punters gambled £5.6bn into the fixed-odd betting terminals (the industry term for the high-speed roulette machines, often abbreviated to FOBTs) every year. By comparison, the 50 constituencies with the lowest levels of unemployment only had 287 betting shops, with 1,045 terminals (a maximum of four terminals is allowed in each shop under the 2005 Gambling Act) and only £1.4bn was gambled on them. Overall, £40bn was staked in the year to March 2012.

The study showed that more than £150m was spent on betting machines in Slough last year, the highest amount in the south-east. It also showed that Slough had 28 betting shops with 102 of the roulette terminals, more than in any other constituency in the south-east.

Slough's population has changed dramatically over the past two decades, so that there is a much higher proportion of people from eastern Europe, Pakistan and India. There is a stark generational and racial divide in the betting shop. Throughout the day the seats in front of the bank of flat-screen televisions, which are broadcasting live from the dog tracks and the horse races, are occupied by older men, mostly white, drinking cups of tea and passing the time of day as they make small bets on the races. The men who come to play the roulette machines are younger, eastern European and Asian. This reflects the British Gambling Prevalence Survey's 2010 findings that problem gamblers were more likely to be Asian or British Asian, to be younger adults, more likely to be unemployed and in poor health. Only one woman comes into the shop while I'm there, and she looks as if she is accompanying a friend and doesn't spend anything.

The government is uncertain how dangerous the machines are, stating in a review published last month that there was "no clear evidence" to prove whether the machines "had any significant effect on the level of problem gambling in Britain". The report concedes: "It is a statement of fact that some players are harmed by gambling on machines" and "it is indisputable that some people are at risk of spending far too much time and money on them". In order to gather some firmer evidence, a £500,000 study has been commissioned from the Responsible Gambling Trust into the machines, but it will take 18 months to complete, and meanwhile campaign groups such as Gambling Watch say the machines should be banned from the high street.

Biscuits and sympathy in Slough. Photograph: Graeme Robertson

A number of punters using the machines in the Roar betting outlet agree. A 33-year-old local man in glasses pops in and out of the shop through the morning and early afternoon, disappearing to the cashpoint and returning with £20 notes, which he slips into one of the roulette machines. It is a cold morning, so he keeps his hood up, but the shop is warm and welcoming, with free tea and coffee available, and sweets and biscuits on the counter. When he has lost all the cash he has, he tries to withdraw money from the cashier using his debit card, but the card is rejected. He finds 10p unclaimed on a machine, so he prints out a receipt, cashes it in with the manager and stakes a final 10p on roulette. He loses.

"They are fun if you win, but mentally they put pressure on you. You feel down if you lose. It doesn't sink in straight away, maybe only an hour or two later when you go home," he says. "They do destroy lives. People can't control themselves ... like me today. I was up £100, but afterwards, the more I had, the more I fed the machine. You're winning, but you can't stop yourself. You lose a sense of the money's value when it is in the machine. It's just a number.

"Even when you win, you still feel miserable. You think: 'Why did I go in there in the first place?'"

He thinks he has spent £300 in the shop over the morning, but Annie thinks it is less than that. She knows this man, too, and describes him as a bit vulnerable and easily led. She doesn't think he is working, although he also describes himself as an occasional car salesman.

He finds it easier to stay away when he is working full-time, but points out that at the moment not many people are buying cars. He has a noticeable physical, shuddering reaction when behind him the soft and husky female electronic croupier tells a new punter: "Place your bets please." "She eggs you on. I've seen screens smashed. I've seen people under so much pressure that their nose begins to bleed," he says.

He thinks he will be able to take some more money out of his account tomorrow (the remains of his savings from when he was last working) and will be back.

Next to the terminal there is a framed poster that declares: "Let's keep it fun!" and offers a number for Gamcare, the problem-gambling helpline. But the terminal's screen dances with enticing advertisements for new games – "Banker's Bonus" and "Arabian Charms", illustrated with a bare-chested, bronzed genie conjuring up gold coins from nowhere.

Tony Harris, 70, a retired potato salesman, comes every day when his legs feel strong enough for the bus ride. He has been gambling since he was 16 when his first bet, on a horse called Monowin, at 40-1, won him £10. "That was a lot of money then; that's what got me hooked." He took his girlfriend and her parents out for a meal. Now he puts whatever is left after the rent and shopping are paid for on the horses, and today has selected Siberian Tiger as a possible winner at the 3.50 at Ludlow.

By early afternoon there is a friendly gathering of four men, talking and watching the races. In between races they laugh at each other ("That man, he'd bet on anything, he'd bet on two snails"), they talk about the news, and discuss the gay marriage vote. "I'm completely homophobic. I can't help it," one of the men declares. "That Elton John, where did he get his baby from?" another wonders.

Later, Charlie, 87, who comes most days as an outing from his retirement home, begins to talk about his time in the army, and how he was in the 4th Dorsetshire regiment when they went in to burn down Belsen. "I remember going in there, but I don't remember coming out. They brought me out in an ambulance," he says, explaining that he wasn't able to cope with the shock. "There were skeletons, skin and bones, bodies lying about, and the stench of the camp. I've only started talking about that now. People wouldn't believe you, would they?"

The men who come in to play the roulette machines do not talk to each other. They play quickly, silently and leave.

"I've never been on those machines. It's only for mugs. People get hooked on them. They put their money in, money in, money in," Charlie says.

Betting shops are more concentrated on urban high streets. Photograph: Simon Leigh

But the older punters realise the betting shops would probably go bust without the roulette machines. William Morgan, 72, a retired coach operator, who once had a gambling problem but now spends only £2-3 a day, says: "Quite honestly I don't know how the betting shops would survive without them. You can't rely on the horses any more."

George Moakes, Roar's operations director, says that about seven years ago, betting shops would make around 85% of their profits from over the counter bets on football, horses and greyhounds; now that has dropped to around 50%, with the rest drawn in from the machines. Fewer people understand how to lay bets on horses, he says, and competition from internet betting has taken some of the bigger punters away from high street bookies, and even their online outlets, in search of the most competitive odds.

He points to the complex, small-print daily racing information pinned to the noticeboards as partial explanation, suggesting the cultural knowledge and linguistic ability required to follow horses, jockeys and trainers could be beyond a lot of his customers. "They struggle reading all this, but the roulette machine is simple," he says.

Sheffield has been working in betting shops in the area for 31 years, and also laments the dwindling numbers who follow the horses, which she sees as a safer way of betting. "It's easier to be in control if it's the horses and the greyhounds, but the new generation have grown up with roulette – they haven't got a clue about the horses. The older ones might follow the horses, the jockeys, the trainers. The young ones wouldn't take the time to look at the form. It's a shame really."

She has noticed that punters betting on horses are more likely to be philosophical about losing. "If you bet on the races and you don't win, you think, I'm having no luck today, I'm off. But with the machine there is more of a buzz."

She knows when trouble is likely to break out. "I know by their mannerisms. They get louder and they bang the screens and they might kick the machines, then they come up and tell me the machines are fixed. We say: 'They're not fixed.'

"We had a Ukrainian guy who spent all the money he was meant to send home to his wife. He came up and told me he needed this money to send home to his wife and he lost it all in the machine. He was a bit teary-eyed. I can't just physically give it back to him."

She advised him to sign up for the industry's voluntary self-exclusion programme, pledging not to return to the shop for an agreed period. Behind the counter she has a pile of half a dozen documents, detailing the customers who have decided to exclude themselves from the shop. The typed document begins: "I request that I be refused entry to the above shop for a period of … months." Each document has a passport photograph of the individual stapled to it. Some men are brought in by their wives and made to fill the forms in.

But Sheffield is not convinced. "I don't think it does help, to be honest. He could go somewhere else and do the same. There are so many bookies around this area. They're not all going to know him. He has probably done a little bit of damage to his life."

On one stretch of Slough High Street, a mile away, there are two Bet Freds, a Ladbrokes, William Hill, Paddy Power and a Cash Converter.

Slough's Labour MP, Fiona MacTaggart, says she has been concerned for a while about the proliferation of high-interest loans shops, pawn shops and betting shops on Slough's main drag. "I think we have stopped realising how risky gambling is. I don't want to be pious, but I think some people don't do it for the joy of a flutter. They do it because they want the money," she says. "My impression is that it has accelerated in the past five years. I'm worried that we have a normalised attitude to gambling which says this is a reasonable way to enhance an income. It is worrying that people will go hungry and their families will go hungry because they feel that gambling will provide some kind of solution."

The Fairer Gambling research has been contested by the industry, which states that it is not targeting poor areas, but simply sets up shops where there is customer demand, and points out that poorer areas tend to be more densely populated. The Association of British Bookmakers says the overall number of betting shops has remained constant over the past 10 years at around 8,500, but the locations have shifted, with more of a concentration now on urban high streets.

Peter Craske, the ABB's spokesman, watches as the morning's biggest spender feeds £340 into Roar's roulette machines. He doesn't see that level of spending as problematic. "Why does that mean he has a problem? It's quite a big leap to conclude that because he spent that much he has a problem – if he has that money to spend. We'd just be speculating," he says. He mounts a fierce defence of an industry that employs 40,000 people in the UK and which he says pays £1bn in tax every year. "People aren't dragged into betting shops. Eight million customers come in every year. They come because they want to, they like the good atmosphere."

The Fairer Gambling figures are unverified, he says, and neglect to point out the 97% payout rate on the machines, which have a fixed profit of 3%. But this rate of return to the player doesn't seem to be reflected in the takings on the machines in Slough's Roar the day I visit. By 6.20pm, £1,593 has been put into the machines and £714 has been paid out, giving the shop a profit of £878.

Naseem Khan, the new father, is back again at 6pm, and quickly feeds £65 into a machine. He places small bets all over the table, listening to the twock, twock, twock as he lays down simulated counters on the table, before whacking the spin button with his fist. He wins £72 and sighs "Thank God" to the screen.

In the evening there are fewer live races, and the screens begin showing virtual greyhounds racing at a fictional track, Millersfield, with live commentary on how the pixelated dogs are faring. These virtual dogs look fatter, less wild and sinewy than the real thing; their tails curl unnaturally.

A steady flow of young men, playing rapid games of roulette and then disappearing, continues throughout the evening. Even those who are winning say they would like to see the machines disappear.

A student from India is trying to win some money to make his weekly allowance of £60 go further. Today he plays £5 and wins £40 and is going to go next door to Tesco to buy some food. On the days he doesn't win he reduces the amount he eats that week. He would be in favour of a ban, and says the machines are "not good for us".

Bob, 31, a Heathrow baggage handler who won't give his full name, has been coming in three or four times a week to play on the machines since a friend introduced him to them a few months ago. He seems somewhat in denial about how much time he spends in the shop. "Not a lot. I try to stay out as much as I can."

He wins £130 and cashes in the money. "Some days they are absolute darlings," he says of the machines, but he would still like them to be removed.

"They are horrible. They really are. I only play them for a bit of fun, but it depends how greedy you are going to be. Me personally? I think they should be banned. They are deadly."

Some names have been changed