Funnily enough I was at an Electricity at Work course yesterday and they discussed that very thing. Electricians should have gone through the Joint Industry Board Electrotechnical Training Scheme, after which they will have a Grading Card which will show if they are an Electrician, an Approved Electrician or an Electrical Technician. http://www.jib.org.uk/

Okay, the point made by the course presenter was that competence is a tricky area here as there is no common definition of an Electrician or their skillset. This is in contrast to gas engineers who MUST be deemed competent by Gas Safe Register and carry a registration card. There are some electrical qualifications which do not include safe working practices such as lockoff, and therefore this would not be deemed as being sufficient for the person to be able to describe themselves as competent. They must have certain core competences such as understanding of hazards and risks, understanding the systems they are working on, understand and be able to implement safe working practices, know when it's unsafe to continue. If you don't ask for JIB training and grading card, then what will you ask for instead? How will you satisfy yourself that your electricians are competent?