Ms Morris just scraped a pass but she was shaky on her quangos

The Education Secretary, Estelle Morris, has made a single political error in "Examgate", the fiasco in which some A-level grades apparently bore only a passing resemblance to the performance of the students. Ms Morris is neither devious nor foolish enough to initiate such a reckless and thoughtless manoeuvre herself. Direct responsibility for the darkly comical incompetence will almost certainly lie elsewhere.

But that is where she has fallen into a trap that has engulfed other ministers before her. Because the fiasco was almost certainly not directly to do with her, she chose to keep her head down for several days while the shambolic story was brewing. This was not her responsibility. She is only the Education Secretary.

Ms Morris is the latest minister to inadvertently reinforce a soundbite David Blunkett crafted earlier this year. In the midst of a storm about rising crime, the Home Secretary perceptively observed that quite often ministers had "responsibility without power". He was commenting on the fact that he got blamed for rising crime, and yet had limited powers over the way police officers sought to deal with it. In the case of the Education Secretary, she too had limited powers. Apparently this dispute over grades was entirely a matter for a body known as the Qualifications and Curriculum Authority (QCA).

The never-ending rise of such bodies is an under-reported modern-day phenomenon. Ministers in Whitehall increasingly opt for a hands-off approach, leaving policy delivery to others. As a result, there is utter confusion over a wide range of policy areas about who or which body is responsible for what. In the case of Examgate, previously anonymous individuals have emerged from the darkness to explain, or try to explain, what went wrong. Evidently these individuals have had more direct involvement in delivering this government's obsession with exams than the elected ministers have.

Last week Sir William Stubbs, chief executive of the QCA, hit the airwaves to admit that "something untoward has happened over this year's exam results". That is one way of putting it. A cock-up on a monumental scale is another way. But who the heck is Sir William Stubbs?

I am not blaming Sir William for his lack of prominence. It is not his duty to choose to be famous, but his relative obscurity raises questions about public life and the way public life is reported. There are Sir Williams everywhere, anonymously responsible for the delivery of a huge range of policies. When Chris Smith became Culture Secretary in 1997 he raised questions about the running of the National Lottery. He hinted he might do something about it. But before long he realised there was not a lot he could do about it. That was a matter for the National Lottery Commission. What about the level of the minimum wage? Ah, that is one for the Low Pay Commission. All right then, what about the mighty Chancellor's views on interest rates? Well, that is nothing to do with the mighty Chancellor. That is a matter for the independent Bank of England.

Quite deliberately, in some cases, insecure ministers have stepped back from being associated with awkward decisions. When John Prescott was given his huge department in 1997 he set about creating a Strategic Rail Authority to take decisions that he could have taken himself. Mr Prescott was not going to take the blame for the wretched trains; much better to hand over the reins to a quango. The quangoisation of Britain has reached such a point that, to take one example, the Department of Environment, Food and Rural Affairs liaises with more than 4,000 agencies of one type or another.

But to the horror of ministers the new political landscape has not worked in their favour. When all is going well the agencies tend to get the credit. When there is a crisis the ministers get the blame. The Government is in trouble when the trains do not run properly, which means on this issue it is in deep trouble most of the time. When the floods of recent times have overwhelmed some parts of the country we do not curse the Environment Agency, we wonder what the Government is doing about it. When A-level students are given a grade that has no relation to their performance we turn to Estelle Morris.

In some cases the distancing between government and decisions has worked well. The decision to make the Bank of England independent has been an unequivocal success, central to the relative economic stability that has been the backdrop of the past five years. But the increase in agencies and quangos, and the corresponding response from ministers that policies are nothing to do with them, is getting out of hand.

Mr Blunkett's solution to the conundrum of having responsibility without power has been to acquire more of the power for himself. In his case this was the courageous and correct approach. The buck stops with him so he needs more power to make sure the police function efficiently. I would not be surprised if the Transport Secretary, Alistair Darling, who will soon become tired of getting the blame, seeks to acquire more direct control over what happens on the railways and the roads.

The solution in some cases is probably less drastic. Ministers must accept that in the end they will get the blame, so they need to take a much closer interest in what these agencies are up to. This is not an entirely satisfactory situation, sending out a message to these bodies that they will have the freedom to deliver services on the ground, but only if ministers approve of what they are doing. But it is not that different from the current bizarre relationship, whereby ministers set the terms of reference to an agency, and then get the blame if the agency fails to deliver.

Newspapers and broadcasting outlets are stuffed full of interviews with ministers, shadow cabinet members and other politicians. The focus is all wrong. Politicians have never been less powerful, nor more ubiquitous in the media. It is high time we found out what some of these agencies are up to. However, I am the first to admit the problem: an interview with the acting deputy vice chairman of the dangerous dogs agency is not going to grab the headlines, although if such a person existed, he or she would wield considerable power, at least over dogs.

Usually lessons precede an exam. In this case the exams preceded the lesson. Agencies are running Britain in the shadows. Some of them are not making the grade. Ms Morris's single error was to assume that because she did not have the power she did not have the responsibility either.