In addition, depending on why he is certifying it,
This is the real point. If to satisfy myself it is all safe then I can inspect and test without a problem. If I am doing work under Part P and I have paid my fee to LABC then I inspect and test and they consider if they accept my results or if they retest part or all to confirm my results. The LABC is responsible so if I completely mess up there is very little come back to me the LABC will have to explain why they accepted my results.
Of course they are not daft and will want to know how much knowledge you have.
If however you were selling a house then unless you were daft you would want to be able to cover yourself against making a mistake. If you said the installation was A1 and in fact it needed a rewire then you would not want to pay for that rewire. So being sensible you would want to insure for professional indemnity and in this case it would depend on what proof the insurance company wanted that you were competent.
The third case would be if it came to court. Here you would have to prove you had the warranty of skill required. In the same way as the companies who sold mine detectors that did not work have been taken to court for fraud you could also be take to court for fraud if you said a house is A1 and it was not.
If one has been working as an electrician for 30 years then with no formal qualifications one would still be seen normally as having the warranty of skill. However if one has made a huge mistake it would be hard to argue the point and only if minor items were missed would one likely win a fraud case.
However with formal qualifications it is far easier to show you had warranty of skill and easier to argue you made an excusable mistake.
However again if no mistakes are made even with no formal qualifications or experience it would be impossible to prove any case against one.
An employer has a duty of care to ensure his employees are trained for the work required from them and if he was to employ anyone without the necessary training then he would also be in breach of health and safety laws. So if an estate agent wants to employ an electrician he must be able to show he had a duty of care in selecting one who could do the job.
Since the estate agent is not an electrician the only way he can do this is to go by formal qualifications either exams or because they are a member of an overseeing organisation.
So in real terms what you stated is correct but in theory you don't need any qualifications.
