Grade inflation is mostly due to an increase in incredibly simple non-subjects like Critical Thinking, imo. That, and the ability to resit exams as much as you want, and redrafting coursework.

I heard they split up Science GCSEs into two exams over the two years (similar to AS/A Levels) or something recently. I had a look at a 'first year' GCSE Biology past paper and it was just...pathetically easy. It wasn't so much science as using common logic to read charts and tables.