I am British, and I am continually told that we have not been invaded since 1066. That whiffs of utter nonsense to me, just some patriotic chest beating which ignores actual history. British history retelling has a horrible tendency to ignore actual history leaving a shallow reinterpretation of what history is, and the older I get the more I see how much of a facade what I have been told actually is. See, for example, all the pomp and circumstance around Magna Carta, which ignores all the facts of what Magna Carta is, and how it does not really mean what people say it does. So, I turn to you, some learned historians.

When was the last time the British Isles were invaded by an enemy force? If possible, separate out successful invasion from unsuccessful. If also possible, explain why other extant invasions do not seem to be counted when discussing invasions.

For the purposes of distinction, let's classify an invasion as an actual enemy army landing on mainland British soil, to filter out weird instances of either single men or small groups.