clicking brakes on 206

[mjc13103]

I recently purchased a peugeot 206 which has started to make a clicking sound from the front left side.

It only does it when the brakes are lightly applied not when you are braking hard.

The thing is, the noise continues when you release the brakes, unless you last applied them hard in which case there's no clicking noise at all.

Any ideas as to what it could be would be greatly appreciated.

P.S. I should mention that the frequency of the noise DOES increase and decrease with speed, so it's obviously a moving part that's doing it but the disk looks fine and the car's just gone through an mot with no problems found.