I have just fitted a kitchen light. I have followed the instructions, Green/Yellow to Green/ Yellow, Blue to Black and Brown to red. When I put the power back on, the lights come on and look really good however, the wall switch does not work, all other switches work fine. Can you help?

If you only disconnected an old fixture and reconnected a new fixture to the same wires, then sounds like the switch is defective.

In any case, you probably need to trace the wiring rom the swithc to the light so you know exactly how the switch is wired and which wire is controlled by the switch.

For a light fixture you should have a white somewhere. Are you in the US? Is this 120 or 240V? What are the colors of the wires in the switch box, and how are they connected to the switch?

The color code mention is typical in the UK. They do not use White neutral, If I recall, blue is their grounded conductor of a 230-240 volt system.

Plus the word "fitted" sounds like the UK.

I was starting to think this was not US, Brian