By Caren Bohan

LONDON, July 26 (Reuters) - U.S. presidential candidate Barack Obama, on a tour abroad where he has got a rock star reception, will wrap up his trip on Saturday with talks in London on the Middle East conflict, Iran and Afghanistan.

On earlier legs of his trip, Obama drew a crowd of 200,000 people in Berlin and elicited effusive praise from French President Nicolas Sarkozy at the Elysee Palace in Paris.

But the Democratic White House contender's visit to Britain is likely to be more low-key.

Obama will have breakfast with former Prime Minister Tony Blair, now a Middle East peace envoy. He then meets Blair's successor, Prime Minister Gordon Brown at 10 Downing Street and holds a news conference.

His final meeting is with opposition Conservative Party leader David Cameron, a possible future prime minister whose party enjoys a strong lead over Brown's Labour Party in opinion polls.

Obama, who faces Republican John McCain in the Nov. 4 U.S. election, began his overseas trip in Afghanistan and Iraq. His week-long tour aims to burnish his foreign policy credentials and counter McCain's criticism that he lacks experience.

Obama's early opposition to the Iraq war accounts for part of his appeal with the European public. He has called for a refocusing of U.S. efforts on Afghanistan and an end to the Iraq war. He also wants Europe to contribute more in Afghanistan.

In addition to talking about Afghanistan, Obama and Brown will discuss Iraq, the Israeli-Palestinian conflict and Iran, according to a spokesman for Brown.

The two will be able to compare observations on the Middle East since Brown also recently visited the region. Obama stopped in Israel, the West Bank, Jordan and Kuwait -- as well as Iraq.

Sarkozy, at a joint news conference at the French presidential palace, joked with Obama and lavished praise on him.

"Good luck to Barack Obama. If it's him, France will be happy and if it's not him, France will be a friend of the United States of America," he said.

Brown, by contrast, is following protocol to ensure that he does not appear to be favouring a particular candidate in the race between Obama and McCain.

There will be no handshake between Brown and Obama at the front door of Downing St as would take place with a visiting head of government. The two also will not hold a joint news conference. Instead, Obama will be solo for question-and-answer session with reporters on the street. (Additional reporting by Adrian Croft; Editing by Dominic Evans)

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