In which conditions are your anti-lock brakes most unlikely to prevent skidding?
In foggy conditions
At night on unlit roads
On loose road surfaces
On dry tarmac
Anti-lock brakes may be ineffective on gravel or loose surfaces. They may also be ineffective in very wet weather, when water can build up between the tyre and the road surface; this is known as aquaplaning.
You may also be interested in these theory test questions