300tdi disco brake problem ?

hi all i have an issue with my disco hoping someone can point me in the right direction,
im sure this has been posted before its most likely a common fault... but here goes.
when im going slow and i put my brakes on theres a judder coming through the brake pad, now is this my bakes causing the problem or is it a wheel bearing ? or niether ?
can anyone help me out, thanks if you can....

Do you feel the judder in the brake pedal or steering wheel?

I would start by checking the pads to see if they are wearing unevenly or just may need renewing, also check the discs are in good condition, to check the bearings get the wheel up off the ground and hold the wheel at the 3 and 9 oclock psition and try and move it by pulling and pushing it to see if there is any movement, then do the same in the 6 and 12 oclock position

judder on the brake pedal is knackered rear discs... judder on the steering wheel is knackered front....

thanks guys for all help.... found the problem.... just needs new rear pads, discs and wheel bearings...