Vibation/Knocking on Braking

When braking normally, a loud juddering/knocking is coming from the front wheel area. If pressure is increased on the brakes, then the noise goes. I think the tyres need balancing, but in my experience, the juddering cannot be caused by this. I have also looked underneath, and there seems to be no damaged bushes. Also, the car had some new bushes just before I bought it 3 months ago.

Can anyone help with this, as I want to make sure the car is safe?