I lived and worked, sometimes as a teacher, in several different countries over the years. Now I hear what's going on in Britain and elsewhere from friends, children and (directly) from grandchildren. Worldwide, different countries have different problems with schools. Britain has a particular problem, given the structure of its education system.
In Britain recently, the general deterioration in public services has - of course - impacted schools as well as health services and elsewhere. Overall, this is political. Perhaps without realising it (!) a majority of you, my fellow citizens, consistently voted for governments which did this - accentuated the move towards, as J.K. G. said, long ago, private affluence (now in fewer and fewer hands) and public squalor.
(No, as I feel many of you itching to point out, the solution will not just require "throwing money". That will be a necessary part of any solution, though. Tax the rich and listen to Gordon Brown ...)
--But there's a particular difficulty in Britain which, for some reason, often gets less discussion than it demands. This is the unique educational apartheid which pertains here, under which a minority, including most of the wealthy and powerful, arrogate educational resources to themselves while denying them to the majority. (7% ... 93%?)
It's true the education obtained by this minority is itself abysmal. (If you doubt which, look again at products of Eton, Westminster etc., and ask how come their awfulness is so ubiquitous; "by their fruits ..."?) Nevertheless, that these holders of the nation's purse-strings so solicitously keep their children so far from the nation's schools has had all-too-predictable results, including the woes adumbrated in this MN thread.
What to do? Well, Britain remains a democracy. Change is possible. Let us not despair.