Help please, ignition light comes on when braking?

Hi there, I'm hoping there is someone out there that can help me,

I have a BMW 316i Compact on a N plate, its nearly due for a service but my concern is that I'm see now with more regular occurance that when I brake the ignition light comes on then goes off?? this is really puzzling me and getting me worried with a huge garage bill?

Help please....

Help me please someone, I have been advised it may be brake fulid warning or a brake warning sensor

Check your brake fluid,may be low and causing the warning light to come on.