Narrator: In September 1939 Britain declared war on Germany, joining the biggest war ever fought in history.
But how did it start? Let's rewind.
Since Victorian times, Germany had been a very large and powerful country at the heart of Europe.
But when it was defeated in the First World War in 1918, Germany had to give up a lot of its land and pay harsh penalties as punishment.
It was also forbidden from having a large army or navy or any air force at all.
This made many Germans very angry. On top of that, in 1929, the Great Depression hit.
There were shortages of food and money all over the world, including in Germany. People lost their jobs and money began to run out.
In 1933, Adolf Hitler became the Chancellor of Germany.
Many Germans desperately hoped Hitler would bring change and make life better. He lead the National Socialist Party, the Nazis, and promised to make Germany a powerful country again.
But Hitler also spread hatred. This hatred would eventually lead to The Holocaust, the killing of millions of Jewish people, as well as gay people, disabled people, political opponents, and ethnic groups like the Roma people or the Poles. Simply because of who they were.
Hitler believed that the German race was naturally better than other people, and therefore were entitled to dominate all of Europe.
He planned to forcibly take back all of Germany's lost land as well as capture parts of other countries.
He started in 1938, by sending soldiers to take over, or occupy, Austria and parts of Czechoslovakia, which is now split in to Czech Republic and Slovakia.
Then in September 1939, German troops invaded Poland. Britain and France had agreed to defend Poland against German attack, so they gave Hitler an ultimatum. Withdraw his troops or they would declare war.
At eleven am on Sunday the third of September 1939, Neville Chamberlain, who was the Prime Minister of the United Kingdom at the time, went on the radio. He explained that the British government had demanded that German troops withdraw from Poland immediately.
But the Germans had not responded, meaning Britain was now at war with Germany.
Moya remembers hearing the news.
Moya: I just remembered that my mother grabbed my dad and he was standing, they were both standing as I remember it. The thing that was running through my mind all the time well, yesterday was my birthday and I'd really love that book with the shiny cover that's in Nelly's shop at the post office and will I get it? And if there is a war will you be able to do things like that?
Narrator: Did you know? When the war was announced it wasn't a surprise. The British government had been watching Hitler's advance across Europe for several years and had prepared for the worst.
Moya: People were aware that the possibility of war being declared was in the air. And the year before at school in Hammersmith, we had practiced being evacuated and had our gas masks issued and so on.
Narrator: As well as gas masks, the first air raid shelters were distributed in the year before the war. Plans were also drawn up to
prepare for food, fuel and clothing rationing, limiting how much people could have to make sure there would be enough to go round.
To make the war a success, everyone would have to pitch in. Many men were conscripted into the armed forces. At first, women could choose whether to join up, but from 1941 they too were made to serve either in factories or the services. Even Princess Elizabeth, who would later become Queen Elizabeth II, trained as a mechanic and a military truck driver.
However, despite the detailed preparations for war and the enthusiastic participation on the home front, nobody could have possibly have foreseen how long it would last.
