I am interested in how all this will play out, as I have a little insight into the reality on the ground in independent schools and I think there are a few assumptions being made about the outcome of VAT and charity status changes.
I have taught in state, a middling independent day school, and now a public school. Although there are teachers that move between sectors, I am in the minority in my current school. Most of the staff went to public school themselves and have only taught in the independent sector. Movement here is between UK independent schools and the international market. There has been a big expansion in UK independent schools opening satellite schools in Asia and the Middle East, and I have seen a lot of movement abroad to these schools in the past few years. If the UK independent sector entered choppy waters, I think many staff would seek a move abroad, not to the UK state sector.
I do wonder what people really mean when they say that the government will pay for more teachers for state schools with the money raised from private schools. There is not a queue of people waiting to train to teach. The government are not currently meeting recruitment targets. That is not because there are not enough training places (as with doctors) but because it is not an attractive career. The reasons behind this are really cultural in the UK, and money will not solve the problem. Teaching is held in low regard here.
Some day schools will go to the wall, and there will be a bit of a trickle of kids into state, but I doubt it will be a massive influx. That middle ground between state and public school will just gradually disappear, I think.
So, I'm not sure what this will really achieve. The existence of the independent sector in the UK has not been to the detriment of state provision, in my opinion. Countries that rank highly on PISA tend to hold education in high regard. We should be having a real conversation about how we can change our attitude in the UK. Trying to choke off the independent sector will have little impact on the state sector. It distracts from the real deep rooted issues.