Alexandra Palace is a Grade II listed entertainment and sports venue in London, located between Muswell Hill and Wood Green in the London Borough of Haringey. It is built on the site of Tottenham Wood and the later Tottenham Wood Farm.
This would ensure the Germans did not know their planes were over Westminster.
BBC programmers would also play music to contact Polish freedom fighters.
Using the codename "Peter Peterkin", that would be broadcast following the Polish news service.
Historian David Hendy said: "The bulletins broadcast to Poland would be deliberately short by a minute or so And Then a secret messenger from The Exiled Polish government would deliver a record to be played.
"They would see one which they thought would make a better broadcast and the wrong bridge would get blown up in Poland. "
The coded messages to the French resistance in news bulletins were less opaque and consisted of a few phrases dropped into a programme script or foreign language news bulletin.
BBC transmitters at Alexandra Palace in north London were also used as part of an RAF operation to distort the navigating system of Luftwaffe bombers, so that they were misled about direction and range.
Other items in the archive include several contemporaneous eye witness accounts of bombing raids of Broadcasting House in 1940 and BBC newsreader John Snagge 's account of The Hours leading up to his first broadcast about the D-Day landings when he was kept under armed guard to stop the news leaking out.