Short-wave radio technology allowed signals to be broadcast vast distances. Other countries had already begun international transmissions.
And there was support from the British government and countries in the British Empire.
The Colonial Conference of 1927 showed great enthusiasm for the scheme - although it was less happy to put any money into it. But the BBC, for its part, had practical reservations. Who would pay? And would the programmes be clearly heard across long distances?
Nevertheless, its director general Sir John Reith decided to go ahead with the plan, using money from listeners in Britain who had to pay an annual radio licence fee.
He explained that the BBC would "transmit comparatively simple programmes to give the best chance of intelligible reception." But he admitted that, given the lack of cash, those programmes would be "neither very interesting nor very good".
The Empire Service went on air at 9.30am on Saturday 19 December, from a studio in the newly-built Broadcasting House in London.
It opened with a two-hour transmission for Australia and New Zealand. There were four later broadcasts to other parts of the Empire.
The new service was opened at 0930 by the BBC chairman JH Whitley, followed by the director general Sir John Reith, who told the new overseas listeners that radio was "a connecting and co-ordinating link between the scattered parts of the British Empire."
He had to deliver his 12-minute address another four times over the next 15-and-a-half hours: 0930 GMT, 1430, 1830, 2030 and 0100.
The earliest transmissions were aimed at five areas and were intended for evening listening.
That meant the programmes for Australia and New Zealand were broadcast 0930-1130; India, 1430-1630; East and Southern Africa 1800-2000; and Canada and the West Indies 0100-0300.
But it soon became clear that some transmissions were crossing over to other regions. In some parts of Western Australia and the West Indies, the best reception came from the Indian service, while New Zealand got improved reception listening to the West Africa service.
By 1933, the BBC stopped describing the transmissions by the region for which they were intended.
Talking to the Empire - "for £10 a week"
The early Empire Service programmes were largely taken from the BBC’s output to Britain, to keep costs down.
They included music, variety and events such as Test cricket and tennis from Wimbledon.
The first head of the Empire Service, Capt CG Graves, wrote in his diary in 1937 that he “blushed” when he thought of the opening broadcasts: "But you must remember that all we had to spend on them was £10 a week."
Graves pushed for more money. "What I need is £sd," went one of his appeals.
He managed to get the allowance increased to £100 a week and by the end of 1933, it was £200, though broadcasting hours were also extended.
News received a boost in 1934 when an Empire News Editor and three sub-editors were appointed to prepare bulletins aimed at a worldwide audience.
That same year, an Empire Orchestra was formed, which needed an arrangement with the Musicians Union.
Because the orchestra’s live concerts were often performed late at night or early in the morning, its members were on special contracts to take into account the anti-social hours.
The King speaks
Six days after the opening of the Empire Service, a broadcasting tradition was born: the royal Christmas message.
It was delivered by George V live from the royal family’s Norfolk retreat Sandringham. His speech was not a direct result of the new Empire Service: the BBC had been trying to persuade the King to speak to his subjects for some years - director general Sir John Reith made the first approach back in 1927.
But when the King’s voice was heard across the Empire, it enhanced the reputation of radio as a powerful new international force.
The King made his speech from his small study, using a specially-made microphone enclosed in a wooden cabinet.
The words were written by probably the Empire’s greatest poet and author, Rudyard Kipling, and began: "I speak now from my home and from my heart to you all."
Reith wrote in his diary: "It was the most spectacular success in BBC history so far. The King had been heard all over the world with surprising clarity."
The Empire talks back
The Empire Service did not just broadcast programmes from London.
The fledgling broadcasters in the Empire also sent programmes back.
A landmark rebroadcast came from the top of Table Mountain in Cape Town and was produced by the Africa Broadcasting Company - the forerunner to SABC.
The programme featured a description of the view from high above the south western tip of the continent, looking over two oceans.
It was transmitted by Post Office wireless beam, recorded in London and distributed to other parts of the Empire.
When the World Service celebrated its 70th birthday in December 2002, it broadcast for 14 hours from the top of the mountain, starting when the sun rose over the Indian Ocean and continuing until it set over the Atlantic.
The new BBC service used short wave for its transmissions, and this led to hotly-contested technical arguments.
Because of the poor quality of short wave, it had been confined to amateur radio enthusiasts, while long wave was believed to be the best way to transmit quality signals over a long distance.
It was also believed that radio signals travelled in a straight line, so could not follow the curvature of the Earth.
Only when amateurs discovered they were picking up transmissions from thousands of miles away did that view have to be revised.
Research revealed the short wave signals actually bounced between the Earth and the layer of the atmosphere 150 miles up, known as the ionosphere, enabling them to follow the surface of the planet.
But because the signals were affected by things like whether it was day or night, more research was still needed to work out the best frequencies to use and the most suitable times for broadcasting to deliver the best sound quality.
This is a recording
Because the new Empire Service would be broadcasting the same programmes to different parts of the world, it needed recording equipment.
One way was to record on to wax discs, but these lasted only a few minutes. Longer recordings were achieved using magnetic tape, a system still in its infancy.
The BBC chose a design by German inventor Ludwig Blattner, which used a tape made of thin steel. Its engineers modified these “Blattnerphones” by improving the motor to give a more stable tape speed; and narrowing the tape width from 6mm to 3mm.
By 1932 it was possible to record 32 minutes of sound on them. But there was still enough doubt about their reliability (broken tape was a regular occurrence) for the BBC’s director general Sir John Reith, on the Empire Service’s opening day, to deliver his 12 minute address live on five separate occasions, between 9.30am and 1.00am the next day. "I was very bored with it," he said afterwards in his diary.
A more reliable technique came later in the decade with the introduction of MSS recorders, which cut recordings on metal discs covered in a lacquer called shellac.
These disc recorders - looking like complicated gramophones - were developed during the war years to make them smaller and more portable for outside broadcast use.
Having set up the Empire Service to broadcast in English, the BBC later began to consider foreign language transmissions as well.
This was a time of increasing tension involving the fascist regimes in Germany and Italy, who were already broadcasting across borders.
The top priority was Arabic - Britain was influential in countries like Palestine and Egypt - followed by Spanish and Portuguese, but aimed at Latin America, where Britain had commercial interests.
Latin America was already a target for German and Italian broadcasters, as well as those in France and Holland.
Italy was the main overseas broadcaster in Arabic, and the British Foreign Office was so keen to begin transmissions to the Middle East that it even considered setting up a station of its own in Cyprus.
The Foreign Office also urged the BBC not to broadcast any news in Arabic that might reflect badly on the UK.
But the Corporation insisted on using the same news values it did with its domestic services and refused to broadcast the kind of propaganda being transmitted by Germany and Italy.
First Arabic broadcast
The British government’s fears about the sensitivity of broadcasting to the Middle East seemed to be realised in the first BBC Arabic Service bulletin, on 3 January 1938.
The third news story began: "Another Arab of Palestine was executed by hanging at Acre this morning by order of a military court. He was arrested during recent riots in the Hebron mountains and was found to possess a rifle and ammunition."
Reaction in the Arab world included the King of Saudi Arabia reportedly weeping at the news; and a newspaper in Iraq thundering: "The London radio inaugurated its Arabic programmes by the broadcast of acts of terror in Palestine and of the execution of Arab Muslim youths - a proceeding which even the most Zionist of Zionists would pronounce as representing a lack of taste."
The head of the Foreign Office’s news department, Rex Leeper, commented: "Is the BBC to broadcast to the Empire the execution of every Arab in Palestine… It seems to me unnecessary, though I suspect it gives its conscience a warm glow."
But the head of the Empire Service, JB Clark, justified the BBC’s reporting. In guidance to a sub-editor in the Arabic Service he wrote: "The omission of unwelcome facts of news and the consequent suppression of truth runs counter to the corporation’s policy."
The opening of the Arabic Service was attended by dignitaries from the Middle East, including representatives of Saudi Arabia, Yemen, Iraq and Egypt.
Arabic and Latin American broadcasts began early in 1938, but later that year the BBC also made broadcasts in German, Italian and French.
This came in response to the crisis over Czechoslovakia, which was being threatened by Germany and led to many fearing a wider war.
Two days before Britain’s Prime Minister Neville Chamberlain met Hitler at the Munich conference, the BBC was asked to broadcast translations of a radio address Chamberlain was making to the British people.
The Foreign Office promised to provide translations, but at the last minute, the BBC had to find people both to translate and read in German and French.
The German translator was a Daily Express cartoonist, Walter Goetz, who was tracked down at a cocktail party and told to get to Broadcasting House as fast as he could - even if it meant driving through red traffic lights.
The Prime Minister made his speech at 8pm and each page was then sent for translation and broadcast. Later parts of the speech were still being translated while the earlier sections were being broadcast.
A foreign Home Service
News bulletins in the three European languages continued throughout the Munich crisis, with some of them included in domestic transmissions.
There were remarkably few complaints about hearing a foreign language on the BBC’s normal output, though one misunderstood where they were coming from and complained: "I consider it against public policy to allow the Germans and Italians to take over radio at 7pm. They are both against the British."
Once the Munich crisis was over, the BBC decided to maintain the new services and in April 1939, French, German and Italian were set up as separate services, and their hours increased.
As the threat of war came closer, more foreign language services began. In May 1939, the Empire Service included a weekly newsletter in Afrikaans, and in June, Spanish and Portuguese broadcasts aimed at Europe began.
By the time war was declared on 3 September, 1939, the BBC was broadcasting in seven languages, plus English.