Thanks to British colonial policies of the first half of the 19th Century, India remained the world's largest producer of the leaf until 2006, when China overtook India.

But unlike China, in most of India there was no ancient tradition of tea drinking.

And as late as the 1950s, stern proscriptions by nationalist leaders such as Mahatma Gandhi were dampening domestic demand, and meant India was exporting more than half its tea.

So how did the cuppa overcome such a hostile market to stand at the brink of national drink status?

Viceroy Curzon introduced the Tea Cess Bill in 1903 to tax the Indian trade, raise a fund and promote marketing.

Over the previous two decades China's share of the London tea market had fallen from 70% to 10%, replaced mostly by India's and Ceylon's.

By 1900, tea was a large part of British household spending, but the market, although the largest, was starting to go flat.

The Indian Tea Association, an industry group made up of British companies, turned to the second largest market, the US - the former colony that 150 years earlier had used the opposition to rising tea taxes as a rallying cry for independence.

When the US economy and London tea prices crashed at the end of the 1920s, the association then looked towards the Indian market.

By then the brew was enjoyed by not just the Singphos and Khamtis, the two Burmese-origin tribes in India's hilly north-east that had enjoyed tea for centuries.

It had become a drink for the Indian upper and middle classes in Calcutta, the colonial capital that had become the world's largest tea port.

Cultural historian Gautam Bhadra has gathered a pile of circumstantial evidence on the growing Indian - and indeed Bengali - habit of drinking tea in the 1920s and '30s.

"We became sure of an Indian tea habit in the 1920s not just from the celebratory poems published in the Sahitya magazine," he says.

"Amritalal Basu's 1926 sketch, Pintur Theatre Dekha (Pintu Goes to the Theatre), mentions trouble that erupted when someone tried to hide a shortage of tea by serving boiled neem leaves in earthen pots. It's the first reference of having tea in earthen pots in India."

The "Indian antidote" affected the habits of others, too.