"It really is hard to explain just how different the education received is to a comprehensive school unless you go see for yourself!"
I have been lucky enough to observe normal lessons at both our local SS grammar and our local comp as part of training.
When comparing those two schools - and I appreciate that it is only a comparison of 2 schools, not 2 schooling systems - I agree that the education provided was very different.
Had i delivered ANY of the lessons i saw at the grammar - bearing in mind that the teachers knew we were coming - I would have been graded, at best, Requires Improvement, and probably Inadequate. Pupils sat in passive rows to be told what pages of the textbook they were working from, and the teacher then sat at the computer doing something else while the students worked through the exercises. The only variant was that in Science they were doing an experiment from the textbook, and in history they were doing a worksheet. Students were mainly silent.
In the comprehensive, students were working round tables, or in pairs. There was some direct teaching (including a variety of practical, visual and text stimulus), a lot of group and individual discussion and questioning, and then varied independent work including research, differentiated both by level and by support. Teachers were engaged with pupils throughout every lesson, there was a low buzz of talk about the task.
Both schools thought that they were demonstrating 'good practice' to us the grammar asked us to list 'all the excellent things that we saw in the lessons that we could take back to our own schools'. The comprehensive asked us 'What do you feel worked well for the students, and what would you suggest that we could have done better?'