Though I've no samples to compare, it's not necessarily as simple as the exams getting easier. The way the exam system is set up these days makes it very easy to 'play the system', as it were. Firstly, the course structure is so compartmentalised that effective revision is made simple. Secondly, this compartmentalised approach encourages and rewards an extremely narrow approach to learning - memorising only what you need to know and no more, and memorising it well. Thirdly, much of many courses is made up of coursework, which any fool can get high marks in with a modicum of effort. Fourthly, you get three shots at each exam if you so desire.
There are many intelligent and capable students who for whatever reason do not attempt to play the system, and for them it remains challenging to get A or B grades. The exam system these days is set up such that grades reflect the work ethic of the student far, far more than any other personal quality. Work hard, revise hard, get good marks. Given how useless even a good examination system is at categorising people into intellectual strata, one begins to consider the whole thing a bit of a waste of effort. Exams, that is, not the rest. Basing someone's life opportunities on the strength of their work ethic whilst in the throes of late-stage puberty seems a bad idea to me. Perhaps just me, though.
Also, a lot of people do daft, easy subjects, like sociology, sports studies, on-license management and fence erection. Seriously, a college near here runs a course in putting up fences, and another in barkeeping. Statisticall speaking, each is as valued as chemistry or mathematics.
It should also not be forgotten that a 'pass' is a mark of about 30%, so it's little surprise that most people at least scrape an E. For this reason, less than a C at both GCSE and A level is generally considered poor show.
In short, British education has become less about learning and more about learning to pass exams. 'Exam technique' is taught as heavily as the subject itself in some cases, and not without reason - the vagaries of the marking system are such that lack of practice can be more of a killer than lack of knowledge or intelligence. There is a prevailing trend of reshaping the education system to be less about separating the wheat from the chaff and more about not hurting the chaff's sense of self-esteem. Being the elitist intellectuophilic bastard that I may or may not be, I find all this irritating at best.