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

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