Historian Dr David Starkey has compared Scottish first minister Alex Salmond to Nazi German leader Adolf Hitler.
"If you think about it, Alex Salmond is a democratic Caledonian Hitler, although some would say Hitler was more democratically elected," he said.
"[For him] the English, like the Jews, are everywhere" he added to gasps from the audience.
Starkey was speaking at a debate, hosted by the Bow Group think tank, on the teaching of British history in UK schools.
"England has shaped the world and now the world has shaped England" he said, "every other country focuses on its own history and it's absurd that we don't."
Teaching should, he said, "unashamedly focus on political history. Social history is...mere sentiment".
The British needed positive teaching of their history, Starkey argued, to preserve national identity.
"English national identity is too important to be left to the loons of the BNP and the EDL" he said.
"The government is absolutely hamstrung, as was Gordon Brown, in defining what it is to be British" he added.
Starkey lamented that in the wake of Enoch Powell's controversial Rivers of Blood speech, it was "no longer" possible to speak about nationalism.
The SNP has reacted with fury to Starkey's comments. A spokesman for Alex Salmond told HuffPost UK that Starkey's remarks were "offensive nonsense".
“This offensive nonsense is actually an insult to Scotland and to the people of Scotland.
“David Starkey is getting dafter and crankier with every passing day – his litany of offensive comments are designed only to provoke outrage, and thankfully England is blessed with a great number of far better historians than him.
We can count ourselves lucky that David Starkey is nowhere near the teaching of history in Scottish schools.
“In the words of Robert Burns, Scots will ‘look and laugh’ at this nonsense.”
Meanwhile, SNP Parliamentarian Jamie Hepburn attacked Starkey on Twitter.
And Murdo Fraser, who ran for leadership of the Scottish Tories, said "Would someone please tell David Starkey to keep his trap shut?" (See below for more reaction)
Starkey is no stranger to making controversial comments. Last year he was criticised after claiming "the whites have become black", when discussing the London riots. He also described Scotland, on BBC's Question Time, as a "feeble little country".
Tory MP Dr Kwasi Kwarteng, who was speaking alongside Starkey, said there was a greater need for teaching history.
"We're the only country other than Albania that doesn't have compulsory teaching of national history ... we're in an awful place" he said.
Kwarteng suggested there was a "case" for the compulsory teaching of history up to 16 years old.