The reasons for the longstanding British vendetta against Russia are not entirely clear and seem to have disparate roots: the desire to ensure that no one power is dominant on the European mainland (directed first against France, then Russia, then Germany, then the USSR and again Russia); maintaining supremacy on the seas by denying Russia warm-waters ports, above all the Dardanelles; and making sure territories of a dissolving Ottoman empire would be taken under the wing of London, not Saint Petersburg.
Look, it's a good article; however, it completely misses the neocons and the Zionists in Israel. Yes, the British Empire has always been at war with the Russian Empire, hot and cold. However, the neocons and Zionists hate Russia even more than do the most imperialistic of the Brits. To the Brits who aren't Zionists, Russia is competition, and all's fair in Empire building and retaining. To the Zionists, Russia represents the modern day obstacle to those Zionists ruling the entirety of humanity as slaves. Not all Zionists go quite that far, but there are enough of them who do to make it the rule. Regardless, there's an Anglo-American-Zionist understanding that each will push for an Anglo-American-Zionist global empire and then fight it out for supremacy later on, on intellectual, spiritual, and economic grounds. The Zionists are confident of winning that "end-times" contest. The Brits have been too smug to consider it, at least openly. The Americans had been too cocky to even imagine it.