How fixed odds betting machines work
Fixed odds betting terminals - or FOBTs - were introduced to the UK in 1999, and are a growing source of income for bookmakers.
Between October 2013 and September 2014, they generated more than half of the in-store profit made by the industry - £1.6bn.
Last month, the government rejected a call from 93 councils in England and Wales for the highest stake to be cut to £2 from £100.
The gambling industry also says there are adequate measures in place to help problem gamblers, while the Gambling Commission says there is little evidence tackling high stakes alone will prevent addiction.
But some people have lost very large sums using FOBTs - and there are claims problem gamblers are more vulnerable to them.
Reporter Nick Eardley went to try out one of the machines.
25 Aug 2015