Complex sentence: The realisation of the necessity of civilian evacuation from the Channel Islands came very late, and with no forward planning and secrecy being maintained, communications between the island governments and the UK took place in an atmosphere of confusion and misinterpretation.
Split into simpler sentences: The realisation of the necessity of civilian evacuation from the Channel Islands came very late. With no forward planning and secrecy being maintained, communications between the island governments and the UK took place in an atmosphere of confusion and misinterpretation.