https://www.techradar.com/news/everything-you-always-wanted-to-know-about-age-verification-but-were-afraid-to-ask

The UK 'porn block' is coming into effect on July 15. After this date, all UK-based internet users will have to confirm that they are 18 or older to access adult entertainment sites. 

Given that Pornhub alone received 33.5 billion visits in 2018, with the UK providing the second-most users after the United States, the coming age-verification filter is likely to affect a huge number of people in the UK.