United Kingdom Business Directory: GBR is the ISO 3 alphabet country code of United Kingdom. Currency of United Kingdom is £, which has a short code of GBP. Capital of United Kingdom is London. United Kingdom has the population of 66573504 and approximate area is 243610.00 square kilometers (or approx. 151379.254 square miles). Population density of United Kingdom is approx. 273/Km2 (or approx. 169.6422/mile2)