Landlords Electrical Safety Check

Is it necessary for electrical work in a UK private house to be carried out by a registered electrician?
I took out a private tenancy on a house in England, UK, two months ago. Before I moved in the landlord had had improvements carried out and had done much of the wiring himself. He is not a qualified electrician.
I am particularly concerned about a reading light fitting above my bed. It is in a metal casing, which comes off to show the wires inside. Some of these wires are not entirely encased by their insulating cover/flex and are only millimetres from the metal cover of the lamp. I fear that if the wire meets the inside of the metal lamp, which could easily happen as the case comes off and is very loose, my children or I could receive an electric shock as soon as we touch the lamp’s outer case.
My questions are
Must my landlord have his work checked by a qualified professional?
Am I over reacting?
Who is responsible for investigating such situations if I am not over reacting – would it be the Councils health and safety department?
Thanks for reading this.
when it comes to electricity and safety you can never over react. My experience with landlords in the U.S. is that they are only interested in saving money and most of them are clueless as to what they are fixing. I suggest you check with the locals about this.
Blue Lightning Electrical contractor in Guildford Electrician Inspection and Testing