The UK introduced the Online Safety Act at the end of 2023. It applies to user-to-user services and search services which have "links" to the UK. This means services that have a significant number of users in the UK, or for which the UK is target market, are covered by the Act (even if based outside of the UK). The Act also applies where services are capable of being used in the UK by individuals and reasonable grounds exist to believe that people in the UK face a material risk of significant harm from user-generated content or search content which is available on the Service.
If the law applies to your service, the first step for your business will likely be to conduct an illegal harms risk assessment.