The UK Gambling Commission is regarded as one of the strictest remote gambling regulators. They put an emphasis on fair games, responsible gambling and regulated advertising for casino games.
A casino operator licensed by the UKGC has to follow these regulations or else face suspension of their license, sanctions or hefty fines.
UK casinos also have to offer responsible gambling limits and self-exclusion options. They are also connected to the national exclusion list Gamstop.
What the UKGC also ensures, is that games offered are certified fair. The software providers have to have their RNGs checked and certified by an independent testing company, like for example bmm testlabs or eCogra. You can see the RTP rate of each game in the info tab.
Overall, playing at a UK casino is safe and you can expect fair games with a real chance for a win.