Cars, goods vehicles not exceeding 2500 kg laden weight, invalid carriages, motorcycles and pedal cycles may be parked without lights on a road (or lay-by) with a speed limit of 30 mph (48 km/h) or less if they are

• at least 10 metres (32 feet) away from any junction, close to the kerb and facing in the direction of the traffic flow
• in a recognised parking place or lay-by.

Other vehicles and trailers, and all vehicles with projecting loads, MUST NOT be left on a road at night without lights.

Laws RVLR reg 24 & CUR reg 82(7)