The maximum stake on fixed odds betting terminals is being cut to just two pounds in the UK.
It follows complaints that the machines are highly addictive and have led to gamblers building up big losses.
Punters can currently bet up to 100 UK pounds every 20 seconds on electronic games like roulette.
What are the bookmakers saying?
That the decision deals a blow to their industry. They argue that the terminals are a major source of income for high-street shops which are struggling to stay afloat as younger gamblers move online.
They say jobs could be at risk.
What is the government saying?
The government is rejecting claims it could damage the industry.
Ministers say they are trying to tackle problem gambling.
What they are saying
"These machines are a social blight and prey on some of the most vulnerable in society, and we are determined to put a stop to it and build a fairer society for all," - Secretary of State for Sport Matt Hancock said in a statement.