For the most part the UK just let the Nazis have the islands. Hitler thought that the UK would react to the invasion and rush to aid them, but Winston Churchill gave them up and said they were of little strategic importance. Prior to Nazi invasion many on the islands left to the mainland to escape the inevitable Nazi occupation. The Nazis from then to the end of the war controlled the islands. The Nazis build up fortifications on the islands as part of the Atlantic wall. As the war went on there was some resistance to Nazi rule of the islands but nor really and big fighting as the islanders couldn't really withstand the Nazis. On the island of Alderney all but 6 people left the island which gave the Nazi an empty land to control which they used to build 4 concentration camps. Following D-day the Nazis became even more strict on the islander. The liberation of the islands didn't happened until after VE-day. The last island, Alderney, was liberated on May 16th and is the last Nazi Germany remnants to surrender.