In October 1979, an unusual group of people were sitting around a table in Beijing.

A Zimbabwean activist, two famous novelists, the deputy director of the British Museum, the paramount leader of China Deng Xiaoping, and David Attenborough.

As in, the nature documentary guy.

That same year, Attenborough had launched his landmark show Life on Earth — the kind of documentary he's now known for making.

It took three years to make and it sent him all over the world, but one country he struggled to visit was China.

Not many foreigners were allowed in at the time, so he joined a delegation as a "distinguished British person".

He and the others got to tour Beijing, and sit down with the guy running the entire country in a televised chat.

Attenborough, ever the environmentalist, had a burning question for Deng, one that had never been asked by Western media before.

He asked what China was planning to do about population growth.

Deng said, "At present, we are encouraging married couples to have only one child, and material awards are given to those couples who have only one child."

The identity of the first Western person to ask about the One Child Policy seems to have been a mystery until now, but a transcript of the meeting reveals it was Attenborough who landed this journalistic scoop.

It was confirmation that China had introduced the One Child Policy.

What is the One Child Policy?

Chinese authorities in the 1970s were terrified that the country's population was growing far too fast, and the effect it would have on productivity, and so in 1980 they introduced the One Child Policy.

They wrote it into the country's constitution and monitored people to make sure they didn't break the rules.

Penalties could include withholding work permits and restricting access to housing.

In each city neighbourhood, a family planning clinic was set up, where officials recorded which residents had been sterilised, which were taking the pill and which had signed the promise to have no more children.

In rural areas, people were forced into sterilisations and abortions.

In 1983 alone, authorities performed more than 20 million sterilisations and 15 million abortions.

Productivity increased but the policy was wildly unpopular.

By 2010, the Chinese Communist Party realised that the policy had worked a little too well.

A generation of workers unencumbered by large numbers of children had created astonishing economic growth, but now they were thinking about retirement.

When they did, there would not be enough young working-age people to keep the economy growing.

Chinese officials predicted that relaxing the One Child Policy would lead to a baby boom, which could stave off this problem.

In 2013, new President Xi Jinping began unwinding the One Child Policy, but it was too late. The culture had shifted. Big families had become too difficult and too expensive. There was no baby boom.

Due to a demographic miscalculation, the population peaked a decade earlier than was predicted, causing a shudder through an economy expecting several years more of population growth.

An economy in crisis

In 2013, Attenborough voiced his support for the One Child Policy in driving down population growth, although he said he regretted "the degree to which it has been enforced" and acknowledged that it "produced all kinds of personal tragedies."

But the tragedies are not just personal, they are economic.