"The era of tribal politics is over."

Mr Blair claimed the true divisions opening up across the world were now not between left and right, but between advocates of modern, open societies and closed, traditional ones.

[He] argued that modern political debate in Europe and the US was "no longer between socialists and capitalists but instead between the globalisers and the advocates of protectionism, isolationism and nativism", which he described as issues of migration and national identity.

The prime minister argued: "Most confusingly for modern politicians, many of the policy prescriptions cross traditional left-right lines. Basic values, attitudes to the positive role of government, social objectives - these still divide among familiar party lines, but on policy cross-dressing is rampant and a feature of modern politics that will stay.

"The era of tribal political leadership is over."

The prime minister insisted: "I am loyal to and proud of the Labour party as any Conservative leader is of his party. But across a range of issues, there is no longer a neat filing of policy to the left or the right."

He admitted the new divisions confused natural supporters and as a result the resistance was very strong, from the left and the right.