Third brake light

Sep 28, 2020
7
0
Hinckley
Hi All
Wondering if anyone out there has come across this fault with the third brake light.
Basically what happens is that the third brake has started working with the ignition that is turn the ignition on the light comes on turn the ignition off the light goes off.
When using the brake pedal the light illuminates brighter, all other lights are working normally even the other two brakes lights.
I'm at a total lost any guidance would be much appreciated. Car is a 2009 Leon Cupra mk2
 
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