Brake Lights/Clutch Pedal - HELP

HI, I have just noticed this problem with my car - when I press down on my clutch pedal the brake lights come on. I have looked at my clutch pedal and there is a switch which move's when you put your foot on the clutch...should this be there, what does it do, any other cause's for the brake lights to come on when I press the clutch?? WITTY posted this - if the switch is loose, tighten the switch and then try again. My guess is the switch you are looking at is the brake light switch which should only be operated from the brake pedal.Hi Witty, this switch is on the clutch pedal - it's red about 2in long with two wires coming from it, see picture. Anymore help or info would be most greatful.

Thank you GRB