Under what conditions may a flashing red lantern be used instead of the emergency stop sign, according to the Road Traffic Rules?

1. 1The light emitted by the lamp must be clearly visible only in the daytime in sunny weather.
2. 2The light emitted by the lamp must be clearly visible only in conditions of reduced visibility.
3. 3The light emitted by the lamp must be clearly visible both in the daytime in sunny weather and in conditions of reduced visibility.