"It's war now. Tell the truth - that's our job." This was the message to the BBC's domestic news staff from their editor on 3 September 1939 - the day that marked the start of World War II.
Already, though, the BBC was on a war footing. On 25 August, domestic radio began carrying extra news in mid-morning, and at lunchtime - something new for an audience accustomed to hearing no bulletins until the evening.
The following day brought an invaluable strengthening of the Broadcasting House news operation - with the establishment of the BBC Monitoring Service.
Hundreds of recruits, many of them refugees from Nazism, were given the task of listening in to foreign broadcasters - from a base in the grounds of a country house, at Wood Norton near Evesham in Worcestershire. The monitors were soon covering almost 250 foreign bulletins a day in thirty languages.
The news team also found their own numbers increased - by an influx from television. Just two days before war began, the infant television service had closed down - for fear that enemy aircraft might fasten on to its transmitter.
From the start, there was tension with the government as to how much freedom should be allowed in wartime to the BBC radio news operations and it took time to establish an effective method of working between the BBC and the new Ministry of Information.
BBC staff were seconded to the Ministry - and so-called "vigilants" from the Ministry were on permanent duty in the newsroom, often alongside representatives of the services. An outcry followed the Ministry's announcement that it had appointed a "director of radio".
Against this background, the expansion of broadcasting to listeners overseas continued apace. When the war began, Britain was speaking to the world in English, Arabic, Spanish and Portuguese, German, Italian, French and Afrikaans.
By the end of 1939, the list of target audiences had been expanded to include Poland, Hungary, Czechoslovakia, Rumania, Yugoslavia, Greece, French Canada, and Turkey.
In another sign of the times, announcers on the new Home Service were no longer required to wear dinner-jackets for the evening shift. There is said to have been a sense that standards were slipping when one of them now took to occasionally wearing shorts.