The Archbishop of York has branded suggestions by the British National Party that a "bloodless genocide" is taking place in Britain as "beyond belief".
Nick Griffin, BNP chairman, spoke to the BBC to defend a party leaflet that said black and Asian Britons "do not exist", arguing that calling such people British denied indigenous people their own identity.
But Dr John Sentamu, who was born in Uganda and is a vocal supporter of making St George's Day a public holiday to promote English unity, said it was not up to the BNP to define Englishness.
He said: "You don't have to be a member of the BNP to be clearly English, and it is quite a mistake to suggest that everybody who wants to affirm Englishness affirms that narrow thinking. This 'bloodless genocide'? I think that is just language which is beyond belief."
Mr Griffin spoke to the Report on Radio 4 to defend the party's Language and Concepts Discipline Manual, which says the term used for black and Asian British people should be "racial foreigners".
The leaflet was leaked to an anti-fascist group and seen by the BBC.
Commenting on its content, Mr Griffin told the BBC that although "in civic terms they are British, British also has a meaning as an ethnic description. These people are 'black residents' of the UK etc, and are no more British than an Englishman living in Hong Kong is Chinese," he said.
The manual describes the BNP's "ultimate aim" as the "lawful, humane and voluntary repatriation of the resident foreigners of the UK".
"We don't subscribe to the politically correct fiction that just because they happen to be born in Britain, a Pakistani is a Briton. They're not. They remain of Pakistani stock," he added.
"You can't say that especially large numbers of people can come from the rest of the world and assume an English identity without denying the English their own identity, and I would say that's wrong. In a very subtle way, it's a sort of bloodless genocide."
