The Sri Lankan government has made a formal protest over comments made by the British high commissioner in a speech in Colombo on Monday.
Dominic Chilcott said that he did not think the political aspiration for a Tamil homeland was illegitimate.
Summoning him to the foreign ministry, the Sri Lankan authorities expressed their displeasure over his comments.
They pointed out to him that the UK government had categorically rejected the creation of a separate state.
Mr Chilcott told the foreign ministry that the UK was against the tactics of the Tamil Tigers but did not consider their demand for a separate state as illegal.