Brake Judder

[PHOENIX1]

I suspect its ABS but my SI Disco has recently had some brake juddering at low speeds when coming out my driveway. Is this judder from the abs engaging due to some sort of sensor failure? I've been getting an intermittent ABS warning light after start up but it I'm really wondering if its dangerous to drive it if I do have an ABS problem before the garage can get a look at her?

[NomadABC]

Are you sure it's not just the rust that forms on disks when left overnight in damp conditions. I used to get a bit of it when I reversed downhill off my drive. By the time I had braked at the end of the road it stopped.