In fairness to you, I suspect the government schools (we call them public in the US, but I recall that "public school" means something entirely different in the UK) in your country are much better funded. I may be incorrect.

In the US, public schools are funded primarily by local governments, and are therefore extremely unequal in their funding, even within a relatively small geographic area.

I graduated high school from an impoverished rural county in 1999. The school I attended had a smattering of Windows 95 machines, enough so that about a 1/3 of the classrooms had a computer in it. There were only 2 machines in the entire school with internet access, and they were in the library. This was for a student body of roughly 600.

When I went to university, students from other (wealthier) parts of my home state of Virginia had been in schools where each student had a computer, and all had access to programming courses starting in middle school. Not surprisingly, students from these schools were disproportionately represented in my uni, and my "Intro to Computer Science" course was mostly filled with kids who had been programming for years. It made it very difficult to learn when more than 80% of the students have a huge advantage going in, and give the professors a false perception of how effective the teaching is. I sure hope the UK isn't like that.