The government has not done enough to reduce inequality between the North and South of England, according to a new report.
The Policy Exchange think-tank called for the three million new homes planned by 2020 to be built in London, Oxford and Cambridge.
Criticising ministers for failing to reduce inequality of opportunity in northern cities such as Liverpool, the think-tank said that residents of these cities should migrate to London and the South East.
David Cameron sought to distance himself from the report, saying: "The authors of this report have themselves admitted it is barmy, it isn't, it is insane.
"Regeneration of our northern cities has been a key Conservative theme over the past three years, and one of the first things I did as leader was to set up the cities taskforce to look in to how we can further renew and regenerate our great cities."
The report prompted criticism for suggesting that some coastal cities had "lost much of their raison d'etre".
It stressed the importance of being "realistic" about the extent to which big northern cities such as Manchester, Leeds and Newcastle could regenerate their struggling neighbours, such as Liverpool, Bradford and Sunderland.
"No-one is suggesting that residents should be forced to move, but we do argue that they should be told the reality of the position: regeneration, in the sense of convergence, will not happen, because it is not possible," it said.
Co-author, Tim Leunig, a lecturer in economic history at the London School of Economics acknowledged that some people would "claim that these proposals are unworkable, unreasonable and perhaps plain barmy".
"But the issue is clear: current regeneration policies are failing the very people they are supposed to be helping and there is no evidence that the trend will be reversed without radical changes," he said.
"Internal migration has always been an important part of a dynamic economy.
"For the last decade British politics has been dominated by ministers who represent poorer urban areas and the New Labour government has invested heavily in urban regeneration.
"A future Conservative administration, more representative of suburbs and the South, would most probably have a very different set of priorities.
"If we are to ensure that people in this country have similar opportunities, regardless of where they are born, we need to allow people to move from places with few prospects to places that offer more opportunities."
Policy Exchange chief economist Oliver Marc Hartwich said the report "reaffirms Policy Exchange's long-standing commitment to localism, a commitment we have pledged in our previous reports on urban regeneration".
"All towns and cities should have the right to determine their own policies; and their local councils should be assessed regularly and accurately, and the results of such assessment explained to local people," he said.
"Freedom, responsibility and accountability are the keys to unlocking the potential that exists in our towns and cities."
