@zoras, yes totally unfair!
In my county we only have selective secondary education (it isn't mandatory, but if you don't take the exam you go to a secondary school, there are no comprehensives).
When my son did the 11+ I was a single mother, and due to health problems, spent long periods on benefits. He was disadvantaged (I didn't claim FSM, as I didn't know it offered an advantage, and the internet was still fairly new).
There was no way I could afford to pay for tutors for him. I did buy some books from WH Smith, but I wasn't great at knowing how to do them, so I couldn't help him as such. It was verbal reasoning in those days and to be fair, I think it was fairer. It was mainly common sense and you didn't need to be taught it as such. He passed and went to the boy's grammar, where his peers did mainly come from preps, but still he wasn't disadvantaged academically. His primary was also a good school.
Now we're facing it again in the next couple of months. It is different. The maths questions are NOT something that a child will be able to do, if they've never encountered them before. It is specifically geared now, towards those who have had extensive tutoring and experience in the kind of maths problems involved.
My DD's school went into special measures just over a year ago. The standard of teaching/curriculum, means that no child there will have a clue how to do the tests.