TLDR Britain’s illegal gambling market has reached £16.6bn in stakes, more than tripling since 2019 according to H2 Gambling Capital research shared by the Betting and Gaming Council. Offshore betting stakes doubled between 2023 and 2025, with the steepest growth in the most recent two-year period. The legal gambling market share has fallen from 97% in 2019 to 92% in 2025 as more bettors move to unlicensed sites. Illegal operators now account for nearly half of all UK gambling ad spend and are expected to hold the majority within two years. The BGC warns that higher taxes, tighter rules, and proposed financial risk checks are pushing customers toward unregulated platforms that offer no consumer protections.
Britain’s illegal gambling market has ballooned to £16.6 billion in stakes, according to new research from H2 Gambling Capital. The figures were shared by the Betting and Gaming Council, the trade body representing the UK’s licensed gambling industry.
The black market has more than tripled since 2019. It has doubled in just the last two years, with the sharpest growth occurring between 2023 and 2025.
At the same time, the share of gambling taking place on regulated sites has dropped. In 2019, legal operators handled 97% of all gambling activity. That figure now sits at 92%.
Offshore Operators Gain Ground
Offshore betting stakes rose from roughly £5 billion in 2019 to £16.6 billion in 2025. Operator profits from those illegal sites also doubled during the 2023 to 2025 period.
Separate research from WARC found that illegal operators now account for nearly half of all gambling advertising spend in the UK. That share is expected to become the majority within the next two years.
The unlicensed sites pay no UK tax. They also offer none of the responsible gambling protections that licensed firms