Irn Bru is the most popular caffeinated soft drink in Scotland. It is available throughout Britain, Russia and Canada. Its advertising slogan used to be "Made in Scotland from Girders", although the closest one can come to substantiating this claim is the 0.02% ferric citrate listed in the ingredients (although this could also be seen as a pun on the name of the manufacturer: Barr). In Scotland, it is even more popular than Coca-Cola.
The drink was first produced in 1901 under the name Iron Brew. Other soft drink manufacturers in Scotland, such as Hays or Sangs, produce their own versions of Iron Brew and keep the original spelling, but only Barr, the major vendor, changed to the phonetic spelling in 1946 ostensibly to circumvent government regulations on product naming.
When half-flat, cold, and combined with the previous night's haggis dinner, it is widely reputed to be an excellent cure for hangovers.
Rather surprisingly, it also makes an excellent mixer with vodka, which explains why it sells more in Russia than Scotland (although this information may be out of date).
When McDonald's restaurants first opened for business in Glasgow they did not serve Irn Bru. This was an insult to the Scots who, as a result, picketed many restaurants until the McDonald's Corporation relented.
The manufacturer is A.G. Barr, plc, United Kingdom