What is the meaning of a flashing red light signal at a controlled aerodrome directed to an aircraft in flight?

Question

Question PPL(H) - Private Pilot License - Air Law

QuizVDS · Accepted Answer

Airport unsafe, do not land

QuizVDS · Answer

Cleared to land

QuizVDS · Answer

Give way to other aircraft and continue circling

QuizVDS · Answer

Return for landing, followed by steady green at the appropriate time

Id 71 - PPL(H) EN - What is the meaning of a flashing red light signal at a controlled aerodrome directed to an aircraft in flight?