Shakey steering

[chas27]

Set off after cally been stood in garage for a week and clunking sound came from rear.
Ime guessing that was the handbrake, after slowing down near a speedcamera the wheel starts to shake it, then rights itself till reaching about 40 and starts again.
After a mile or so it goes alright until i put handbrake on and then it starts shakin again.
I think it may be the brake caliper sticking.
Any ideas anyone?

[chas27]

After giving a lot more thought i reckon it wasnt a shake but more a judder.

So ive taken wheel off and the disks seem badly warped.
My guess is that the abs sensor has been causing the judder because of the warped disks.
Anyway ive ordered new disks and pads, hopefully this should sort the problem.