Russia overtook it in 1955. China did it by 1960 and both the US and Egypt had trebled their output between 1950 and 1955.
This was at a time of expanding radio ownership, thanks to the development of portable, battery-powered transistor sets.
Between 1955 and 1965, radio ownership trebled in Communist Eastern Europe, was five times bigger in the Middle East, six times bigger in China and 12 times bigger in sub-Saharan Africa and India.
The audiences themselves were changing. Younger listeners around the world had little recollection of the old, pre-war Imperial Britain, and broadcasters had to aim at these people - not an expatriate white community seeking nostalgia about the Old Country.
The new decade would see a greater effort to speak to Africa and Asia, with a former Bush House man, Hugh Greene, now appointed director general of the BBC. And so the World Service was born.
The original Empire Service, which began in 1932 and changed to the General Overseas Service in 1943, got its new name on 1 May 1965, to reflect a new emphasis on world affairs.
For the BBC’s external services, the 1960s have been called the Decade of Africa.
They saw the start of the BBC African Service and a greater interest generally in African affairs, particularly as more and more countries became independent.
Independence also meant setting up their own broadcasting organisations, though there was often a strong BBC link – many staff were trained by the Corporation.
One pioneer of African broadcasting was Tom Chalmers, a former controller of the main British radio entertainment network, the BBC Light Programme.
He was invited to set up broadcasting in Nigeria, and later was asked to do the same in Tanganyika, which became Tanzania.
Chalmers had already left his mark on the Empire Service in his time as its wartime head of presentation.
The service was less than accurate in its scheduling, and programmes regularly overran.
But because overseas stations wanting to relay BBC programmes needed strict timekeeping, Chalmers introduced a new system with a central presentation suite, featuring a presenter and an engineer, with power to take programmes off the air if they overran.
Chalmers was himself a leading BBC “voice”. He was the announcer who in 1945 broadcast to the world that Hitler had been reported dead.
The relay race
Better signals mean bigger audiences - but the costs are bigger too. The BBC realised back in the 1930s that the way to improve the quality of its signals was to set up relay stations closer to the audience.
The first was in what is now Malaysia, but this was not opened until 1949.
The government-owned station on Cyprus was handed over to the BBC in 1957 after the dust from the Suez crisis had settled.
But in the 1960s, efforts began in earnest to improve relays.
In 1966 the British overseas territory of Ascension Island, just south of the equator in the Atlantic Ocean, became the site for short wave broadcasts both to West Africa and to Latin America.
Ascension Island is about halfway between the two continents, and has been fulfilling a strategic role for nearly two centuries - the Royal Navy used it as a supply base during its efforts to stamp out the slave trade in the early years of the 19th century.
It was also the main relay point in the telegraph cable system linking the UK, Portugal and South Africa, with cables also going out to West Africa and Latin America.
The BBC also built a medium wave transmitting station on the island of Masirah in the Indian Ocean to beam programmes to the Gulf States.
Masirah was also used to relay improved services in Hindi, Urdu and Farsi to Iran and Afghanistan
The Cuban missile crisis
The BBC’s Monitoring Service at Caversham played a key role in the ending of the Cuban missile crisis in 1962, in which the world feared a nuclear war between the US and the Soviet Union.
The Soviet military was building missile sites on the Communist island of Cuba as a deterrent to the US, which already had weapons that could reach Russia directly.
When President Kennedy told his Russian counterpart Nikita Kruschev to dismantle the sites or face the consequences, there was a stand-off which kept the whole world in suspense.
On 28 October 1962, Monitoring heard a Moscow Radio broadcast in which Mr Kruschev gave his response to a letter he had received from President Kennedy.
He said: "The Soviet government has ordered the dismantling of the bases and the despatch of the equipment to the USSR. I appreciate your assurance that the United States will not invade Cuba."
Monitoring immediately contacted Washington through its US counterpart, the Foreign Broadcasting Information Service, and Kennedy responded straight away - even before he received the official text of Kruschev’s reply.
The new relay station at Ascension Island aided a big expansion in services to Africa, both in English and in local languages.
This came at a time when Britain wanted to maintain friendly links with its former colonies.
The African Service began a daily current affairs programme Focus on Africa, featuring interviews with leading African figures and reports from BBC correspondents.
The aim was to give listeners a wider view of their continent. By 1963 services in Hausa, Swahili and Somali had been increased to an hour a day.
There were also efforts to appeal to French-speaking Africa, with a daily bulletin in French for Africa introduced in June 1960, and the French Language Service being expanded again after cuts introduced as a result of the 1957 White Paper.
Some services were lost, though. Albanian broadcasts were dropped in 1967 and the following year, so was the Hebrew Service.
Rhodesia declares UDI
In 1965, the white Rhodesian government under Ian Smith declared its independence from Britain, even though there was no agreement with London.
This Unilateral Declaration of Independence (UDI) led the British government, under the Labour Prime Minister Harold Wilson, to ask the BBC to begin special broadcasts to Rhodesia.
The government hoped they would show white Rhodesians how isolated they were in world opinion, and it set up a medium wave and a short wave transmitter close to the Rhodesian border at Francistown in Botswana for the BBC to use.
Even though reception was not good during the daytime, the authorities in the Rhodesian capital Salisbury (now Harare) banned listening in a public place and by 1966 were jamming the signal.
Ian Smith himself frequently condemned the BBC’s broadcasts, particularly for its programme The World and Rhodesia, which was broadcast five times a day.
There was much controversy about this programme, with some critics questioning the BBC’s traditional stance on objectivity.
Jim Biddulph, a former BBC correspondent in Rhodesia, wrote: "Some of the views reported in The World and Rhodesia were too extreme and might cast doubt on the credibility of BBC news programmes."
But the then director of External Broadcasting (and later BBC director general) Charles Curran argued that if the Salisbury regime found the broadcasts objectionable, it was only because they were directed against its censorship.
Even so, The World and Rhodesia ended in 1968, with Rhodesia still controlled by its white minority.
Just as the Germans can claim the credit for developing the modern tape recorder, they also helped broadcasters make another step forward with the portable Uher recording machine.
This was the first that could easily be slung over the shoulder for outside recordings from almost any location.
The Uher Report 4000 was a reel-to-reel machine, recording on to quarter-inch tape, meaning the tape could then either be played directly from a studio tape player or edited by the reporter.
Many BBC radio journalists will remember their Uher as a trusted piece of equipment and it was still being used in the BBC decades after its introduction in the 1960s.