ST LOUIS - BRITAIN'S US ambassador, in a confidential report, mixed praise with criticism of Democratic White House hopeful Barack Obama, calling him a highly intelligent quick learner who can seem aloof, a London newspaper reported on Thursday.

The Daily Telegraph's Toby Harnden reported obtaining a seven-page letter that the ambassador, Mr Nigel Sheinwald, had written to British Prime Minister Gordon Brown to prepare him for a meeting with Mr Obama just over two months ago.

The letter said the voting record of Illinois Senator Obama has been 'decidedly liberal.'

'But the main impression is of someone who was finding his feet, and then got diverted by his presidential ambitions,' the letter said.

The Telegraph said Mr Sheinwald wrote that Mr Obama 'can seem to sit on the fence, assiduously balancing pros and cons,' and 'does betray a highly educated and upper middle-class mindset.'

Charges of elitism 'are not entirely unfair' and he is 'maybe aloof, insensitive' at times, according to the candid letter.

'He can talk too dispassionately for a national campaign about issues which touch people personally, eg his notorious San Francisco comments (in April) about small-town Pennsylvanians 'clinging' to guns and religion,' it said.

Mr Brown last month praised Mr Obama as a 'progressive politician' who would help ordinary Americans struggling with economic downturn.

Mr Brown's ruling Labour Party would traditionally be allied to the US Democrats.

But the letter also heaped praise on Mr Obama, who is currently leading opinion polls over Republican Arizona Senator John McCain in the race to the Nov 4 election.

'Mr Obama is highly intelligent. Not just savvy - which most people at this level of American politics have to be. But intellectually smart; cerebral,' the letter said.

'His manner is frequently interrogative. He is a quick learner. He has the confidence to surround himself with bright people, and is said to listen carefully to and weigh their views.'

The letter called Mr Obama a 'diligent member' of the Senate Foreign Relations Committee, albeit one who took a low profile in 2005-2006.

Mr Sheinwald detected a potential clash between the British government and an Obama administration over Iran and its nuclear programme. Mr Obama has advocated talks with Iran without preconditions.

'If Mr Obama wins, we will need to consider with him the articulation between (a) his desire for 'unconditional' dialogue with Iran and (b) our and the (UN Security Council's) requirement of prior suspension of enrichment before the nuclear negotiations proper can begin,' the letter said. -- REUTERS