Since when did tea become the drink of Britain?

Following the conclusion to Oz and Clarks recent series of Drink of Britain, many people that I have spoken to have been much disappointed that apparently (according to Oz and Clark) the drink of Britain is tea. However this makes no sense as tea is not even grown in Britain, and is consumed traditionally in places all over the world (especially Asia), and to be honest is not actually that popular over here. They might as well have said water was the drink of Britain! To be honest I was quite disappointed, and you could tell in the last two serises Oz was going a bit over the top with vinyards (when hundreds of superb breweries had still not been covered, not to mention specialist beer styles such as Barley wine and Imperial Russian stout). But at least the series didn’t scoop to the same lows as Morrissey Fox did.