The Battle of Britain Five Months That Changed History, May—October 1940 by James Holland (z-lib.org).epub

Britain’s history he had a duty to return home – and there to do something
that might actually be of real use to the war effort.
There had still been one more evacuation for the Royal Navy to perform.
Between 19 and 23 June, just under 23,000 British subjects were taken from
the Channel Islands. It had been accepted that, because of their proximity to
France, the islands could not be held and sure enough, on 30 June, the first
German occupiers arrived. It was ironic that for all the anxiety about British
interests in the Far and Middle East and over Malta and Gibraltar, the first
British territory to be lost should be part of the British Isles itself, but there
had been no practical alternative to letting them go.
A further mounting concern was the Republic of Ireland, independent of
Britain since 1922, but still a part of the Commonwealth. Despite this, it
was decidedly hostile towards Britain, and following the fall of France the
idea that German troops might use Ireland as a springboard for an assault on
Britain and as a base for U-boats began to take hold. Raymond Lee had
barely arrived back in London before he heard plenty of such talk; it
certainly seemed plausible to him. Part of the 1922 treaty had been to allow
the Royal Navy to use Irish ports, but Chamberlain had let this right go in
1938. At the beginning of the war, Churchill, as First Lord of the Admiralty,
had briefly considered using force against Ireland to get it back. Nothing
had come of such plans, but it was now Chamberlain, in something of a
volte face, who suggested force might be used to get Ireland to give up its
harbours. To complete the seesaw change in approach, it was now
Churchill, fearing US opposition, who opposed the idea. He was, however,
keen to secure use of these crucial Atlantic-facing ports, partly to prevent
the Germans using them and partly so that the navy and RAF would have
bases from which to take the attack to the U-boats. As a quid pro quo for
their immediate use, he proposed offering de Valera, the Irish president, the
post-war unification of Ireland. British Northern Ireland would be sacrificed
for this more pressing need. Churchill gave the job of leading the deal to
Chamberlain.
Yet despite being handed Northern Ireland on a plate, and despite the
offer of protection against any German invasion, de Valera was having
nothing of it. Chamberlain cursed his obstinacy. ‘The moment the Germans
land,’ Chamberlain noted, ‘he will ask for help but not a second before; in
fact, his people would fight us if we came first.’