Probably it’s civil law/tort law, not criminal law. Like, someone can’t go to jail for it, but can be sued over it.

Crimes are only violations of criminal law.

googles

https://en.wikipedia.org/wiki/Trespass_in_English_law

Trespass in English law is an area of tort law broadly divided into three groups: trespass to the person, trespass to goods, and trespass to land.

Sounds like that might be the case.

Trespass in English (and Welsh) law is mostly a civil tort rather than a criminal offence. The circumstances in which it is a criminal offence are usually trespass on educational premises, railway property, protected sites, etc.[failed verification]

Not the case here in the States:

https://en.wikipedia.org/wiki/Trespass_to_land

United States

In most states, a criminal trespass to land is defined by statute and constitutes a misdemeanor. In some states, it may be a felony under certain circumstances (e.g., trespassing on a research facility or school property). Remedies between private parties for trespass may include an injunction or money damages.