What is the middle ground of UK politics?

I have realised that I have no idea what the 'middle ground' of UK politics is. I assumed it meant that we don't really like nuclear weapons, but we'll have them if necessary; we really do like the idea of the NHS; we are generally cautious about immigration, but when there is a crisis we are welcoming; we are pretty concerned about the environment; we distrust those with a lot of money; we are generally keen on Europe, as we know it from holidays; we want a good fair wage for all; we utterly distrust private ownership of railways, and think that at least the possibility of nationalisation is a good thing. We are cautious about money, but good when it comes to charity.

But my impression is that these views are now considered widely left-of-centre by many, even "hard left". I remember the views of the "hard left" in the 80s, and they included universal nationalisation, support for communist states, scrapping all nuclear weapons, workers' collectives running everything.

How did the moderate left end up being now labelled "hard left"? How did nationalising parts of the NHS become mainstream? How did we end up with Labour party shadow cabinet ministers saying that they would match their Tory equivalents when it came to benefit cuts? How did we get so that benefit claimants, many of them disabled or ill, became the target of cuts?

I'm really confused.