It’s 1940, on this day. There is not much food to be put on the table because of rationing, it has been virtually impossible to find butter or bacon although vegetables are still available, despite having to queue for ages for them. However, the miracle is still vivid. Dunkirk was evacuated three weeks ago, the majority of the soldiers are back home, but we know and fear what is to come, if not quite when or how.

Foreboding hangs over the country, the expectation of invasion, despite the bright sounds, the music and optimism on the radio coming from the BBC’s Home Service, apart from the news, of course, from Alvar Lidell, which, even although it always seems positive, we suspect shields bleak truths.

News was censored, not just on the one BBC radio channel, but in newspapers. So we would not have known that Hitler, having conquered France, was today dictating surrender terms to the French, in the same railway carriage, in the same Forest of Compiègne, his country had surrendered in 1918.

But it wasn’t just the news which was censored. Music was too, unless you were wealthy enough to have a gramophone and could buy the shellac 78s in a record shop.

On the Home Service there was a heavy output of classical music by BBC orchestras, and up to three on a Sunday although there was an argument going on about playing "enemy music", particularly from living German composers because, apart from their likely sympathies, they might have to be paid royalties after the war.

This UK Singles Chart exemplified the cross-fertilisation between US and British music, or you could say the American dominance.

Connie Boswell and Bing Crosby were at number one with Between 18th And 19th On Chestnut Street while the Andrews Sisters had four in the chart, top of which was Oh Johnny, Oh Johnny O! – as did Vera Lynn, although none of them then was We’ll Meet Again.

Lynn was by far the most popular British singer. She had a Sunday night show on the Home Service (and the Forces’ network abroad) which was listened to by more than 20% of the population, although there was a vociferous campaign against “radio crooners” and “sloppy sentimental rubbish” which forced the BBC to set up the Dance Music Policy Committee, or the anti-slush committee, which excluded “sickly sentimentality which … can become nauseating”.

Among those to be so judged was Bing Crosby’s I’ll Be Home For Christmas, which might make troops homesick and depressed, and the Mills Brothers' Paper Doll which was banned as the committee “did not think it desirable to broadcast the song’s theme of feminine faithlessness”. The BBC also bowed to what was pressure from a small and middle-class section of listeners and cancelled Lynn’s show.

Second in that June hit parade were Flanagan and Allen, the singing and comedy duo, with There’s A Boy Coming Home On Leave.

Flanagan, real name Chaim Weintrop, was to record what became the theme tune to Dad’s Army, Who Do You Think You Are Kidding Mr Hitler?, but that was after the war and he dropped dead after the first episode was shown, although there may be no connection.

This week’s song also includes a rap precursor, Flanagan and Allen exchanging lines.

Flanagan: "Well, I’m goin’ straight in to the Missus and I’m gonna say 'There’s something I want!, send the kids to the pictures'. And when the kids are gone to the pictures, you know what I’m gonna ask her?"

Allen: "No, Bud."

Flanagan: “How ya been gettin’ on for bacon?”

It was the era of big band music, with Joe Loss and Geraldo just outside the top 20. Both were to feature heavily in years to come on the BBC, with Workers’ Playtime and, later still, Parade Of The Pops.

Loss, later in the war, was one of the many to cover the American song, composed by Frank Loesser, Praise The Lord And Pass The Ammunition. It was written in 1942, directly after the Japanese attack on Pearl Harbour, and it’s about a chaplain, a "sky pilot", who says the words and then begins firing at the diving planes.

It was inspired by a true story. The preacher Howell M Forgy was aboard the USS New Orleans when the attack occurred. The ship’s electrical systems were disabled so they had to pass the ammunition along a line of men, a bucket brigade, and Forgy recalled seeing the men were tiring, which is when he came out with the now-famous words. Later he said modestly: “That’s all there is to it.”

When the Soviet Union joined the war, after Hitler turned his attention from Britain to the USSR, the a cappella group the golden Gate Jubilee Quartet recorded Stalin Wasn’t Stallin’ , including the lines: "Well now, Stalin wasn’t stallin’ When he told the beast of Berlin That they’d never rest contented Till they had driven him from the land. So we called the Yanks and English, and proceeded to extinguish, Der Fuehrer and his vermin, This is how it all began."

Although, of course, it was to end in the Cold War.

There wasn’t just cross-fertilisation between allies, but enemies also, or more accurately co-option.

The song Lili Marleen (later Lili Marlene) was a German love song, put to music from a 1915 poem, and recorded by Lale Andersen in 1939.

It was played regularly on Radio Belgrade, the Nazi radio station broadcasting across Europe, but unfailingly at 10pm every evening when allied soldiers would listen in.

Fitzroy Maclean recalled the effect it had on him when he was serving in the 1942 desert campaign. "Husky, sensuous, nostalgic, sugar-sweet, her voice seemed to reach out to you, as she lingered over the catchy tune, the sickly sentimental words.”

In early 1943, a British army traitor, Norman Baillie-Stewart, working for the German propaganda minister, translated the words into English and Andersen sang that version for the Tommies and Jocks. After the war she received a gold disc for sales of more than a million copies.

The most famous version was recorded by Marlene Dietrich in 1944, on the instigation of the Morale Operations Branch of the Office of Strategic Services, a predecessor of the CIA.

It has been recorded innumerable times since. Who could forget the punk rock band Vennaskond and the Estonian version of the song on their album Usk. Lootus. Armastus. in 1993.

Another big favourite, to be banned by the BBC in 1943 on patriotic grounds, was Don’t Let's Be Beastly To The Germans, by Noel Coward. Who could possibly object to: "Don’t let’s be beastly to the Germans, When our victory is ultimately won, It was just those nasty Nazis who persuaded them to fight And their Beethoven and Bach are really far worse than their bite."

The Italian partisan song, Bella Ciao, sung by the anti-fascist resistance in the Italian Civil War of 1943-45 may have been based on a folk song sung by rice weeders on the River Po basin but it’s still sung to this day.

While We’ll Meet Again may have been Vera Lynn’s most popular song (There’ll Be Bluebirds) Over The White Cliffs Of Dover, comes close behind.

It was recorded in 1942, but was written a year earlier by US songwriters Walter Kent and Nat Burton, before America was in the war, and it is believed to refer to the Battle of Britain.

Bluebirds are not indigenous to the UK but another take is that it refers to the colour of the undercarriages of the British Spitfires and Hurricanes.

Within days of our look back at the chart of 80 years ago, on July 10, these planes, with their distinctive blue underbellies, would be overhead fighting off the Luftwaffe.

This was, as Churchill put it, their finest hour.