There are software patents in EPC countries (which includes EU, UK), but not software patents as such. A sibling noted that USA now requires a real-world effect

There are software patents in EPC countries (which includes EU, UK), but not software patents as such. A sibling noted that USA now requires a real-world effect, that change apparently mirrors the situation under EPC: software here can be patented if it makes a technical contribution, ie it must do something outside of the computer (or something that simulates something outside of a computer! see Halliburton). What is and isn't technical is largely down to convention and can't be readily reasoned over IME. In the UK you only need to be familiar with about a half-dozen pieces of caselaw to be able to make a pretty good guess. It's established caselaw that compression is a mathematical method (not patentable); but you can implement that as a computer program (probably not patentable); but you can apply that to image compression (probably patentable, see Vicom). Any opinions here are my own and do not relate to my employment. This is not legal advice.