Complex sentence: This was a terrible thing to be happening as the British Empire was growing quite weak at that time because of Nazi and JapaneseThreatsyet ratified the Statute of Westminster, it could still be considered a British colony (the Statute was ratified in 1942).
Split into simpler sentences: This was a terrible thing to be happening as the British Empire was growing quite weak at that time because of Nazi and Japanese Threats. Indeed not yet ratified the Statute of Westminster, it could still be considered a British colony (the Statute was ratified in 1942).