The historian Dr David Starkey has delivered a withering attack on current Tory strategy at the party's conference in Manchester. Speaking at a fringe event organised by the eurosceptic Bruges Group, the controversial historian also defended his recent comments on the riots in England, and predicted that Scotland would be too "canny" to leave the United Kingdom.

"This is a Tory party conference that enjoys what it enjoys doing, being in government, except that it is not," he told the audience at the Comedy Store. "It is in office but not in power.

"The Tories were defeated at the last election. That is to say they did not win outright majority. 2012 will see the 20th anniversary that the Tories won a majority at a general election. Twenty years. To find a comparable period in which the Tories did not win a victory in a general election you have to go back the 18th century."

Warning that the Tories would be unable to blame the sluggish economy on the previous Labour government for much longer, Starkey said: "In 2015 the blame for the economic mess will be with the Tories. Why should we expect much better?"

Referring to the storm of criticism which greeted his comments on the UK riots, where he claimed "the whites have become black", he admitted that his comments had been "spectacular in every sense". But he said he stood by his remarks, blaming the riots on "a gang culture that began amongst blacks and spread among whites."

"If you don't believe me, ask Darcus Howe," he said, adding that "In the south of England and the midlands there is a complete vacuum of identity.

"Rioting did not take place in Scotland, Wales and Northern Ireland, nor the poorest parts of northeast England and Yorkshire," he said. "These places have a clear idea of who they are."

He said many of the problems in England were due to a lack of common identity and common purpose. "The rich in this country behave as monstrously as they do because there is no sense of common purpose," he said, claiming: "The City of London has become a city state, complete with a fool jester despot in Boris Johnson."

To widespread cheers in the audience he suggested that to reduce waste in government, the Scottish, Welsh and Northern Ireland offices should be closed, claiming: "They cannot do anything. It is deluded and it is demented."

But he said that he didn't anticipate Scottish independence any time soon, saying: "Until a few years ago the EU would have offered a welcoming and pain-free home to Scotland or Wales, and maybe even Northern Ireland. But the Euro crisis has put paid to that. Scotland is too canny to vote for independence and the euro. Instead it will settle for home rule and the pound."

"You all think I've gone mad," he said after claiming England invented limited government, representative government, capitalism and the rule of law.

Tory activists leaving the fringe had mixed views about the historian's criticism of David Cameron.

"A bit harsh," said one. "I don't agree with most of it, but there are some points in there I would agree with, particularly on standing up to Europe," said another.

"I think because Cameron was a spin doctor, Starkey doesn't like that, he thinks we should have a Prime Minister who's done a proper job," said another.