In 406 AD, the last of the Roman legions in Britain were withdrawn to the continent to support the pretender Constantine III. In 410 AD, Honorius, the victorious emperor, wrote a letter to the cities of Britain saying that from here on out, they were responsible for their own safety. The Empire had abandoned Britain. There are those in Britain who never forgot this betrayal, even unto modern times.
Fast forward 1560 some years, and Britain is trying to decide whether or not to join the European Community. A friend of ours — an old man who was in the Fire Service in WWII and knew so much ancient Greek history that we called him Archimedes — was adamant that because Europe had abandoned Britain in 410, there was no reason to support them in 1973. He said that if the UK gave up their sovereignty like that, he was going to emigrate to New Zealand.
Fast forward another three years. The UK is in the EEC. We are back in the US. We send our usual Christmas card. Some weeks later we get it back “Moved to New Zealand. No forwarding address.”
There have always been Britons who looked with distrust on any relationship with The Continent.