By Maria Golovnina
LONDON (Reuters) - Black belt Russian President Vladimir Putin will lock horns with British leader David Cameron over Syria and human rights during a day of judo diplomacy at the Olympics on Thursday at a time when relations between their two nations are strained.
Cameron will push the former KGB spy, to take a tougher line on Syria, Russia's firmest foothold in the Middle East, and stop blocking Western-backed resolutions aimed at stepping up pressure on President Bashar al-Assad.
He is also expected to raise concerns about what Putin critics see as an intensifying Kremlin campaign to silence dissent and discredit Russia's opposition movement.
Cameron is expected to host Putin, the honorary president of the International Judo Federation, at Downing Street and take him to an Olympic arena to watch judo finals together.
A one-time judo champion in his native city of St Petersburg, then called Leningrad, Putin is likely to be at his combative best during his first visit to Britain in nine years.
For the Kremlin leader, who revels in his hard-man image, the sight of judokas body-slamming each other on the Olympic mat will offer a powerful backdrop to his talks with Cameron.
Their body language and dynamics will be watched closely for any clues on the progress of the talks.
Russia has faced growing Western criticism of its position on Syria, with the United States and Britain demanding Moscow drop its support for Assad.
Western powers believe that ousting Assad is the only way to end the bloodshed in Syria. Russia, on the other hand, provides arms to Damascus and has blocked three Western resolutions calling to increase pressure on Assad.
Apart from Syria, talks will probably touch on Russia's tense political situation where critics say authorities seek to silence Putin's opponents through unfair accusations and trials.
In a letter in the Times newspaper, a dozen leading rock musicians including Jarvis Cocker urged Putin to give a fair trial to women's rock band Pussy Riot, whose members face up to seven years in jail for protesting inside a Moscow cathedral.
Officially, both sides have said talks would focus on trade.
"The sides will discuss what can be done to boost trade. Apart from this, in the course of the talks, the Syrian situation will be discussed in great detail as well as other regional problems," a Kremlin spokesman said.
"We see it as another possibility ... to explain our arguments, the Russian Federation's clear, consistent and transparent position."
Thursday's judo bouts include the men's 100kg and women's 78kg competitions, with the two finals around 1500 GMT. Russia's Tagir Khaibulaev and Vera Moskalyuk as well as Britain's James Austin and Gemma Gibbons are expected to compete in Thursday match ups.
Putin, whose testosterone-fuelled appearances have earned him the nickname "alpha-dog" in U.S. diplomatic cables, is in London - home to many influential Russians and political exiles - on a private visit at Cameron's invitation.
But diplomatic efforts are complicated by Russia's difficult relations with Britain itself, ranging from espionage to human rights to the 2006 death from radiation poisoning in London of Kremlin critic Alexander Litvinenko.
"He (Putin) is not welcome in London, neither by Russians who live here or Londoners themselves," Litvinenko's widow, Marina, who lives in Britain, told Reuters.
"It will not be a comfortable visit for Putin. A lot of uneasy questions will be raised."
Observers said Putin's show of strength in London could be in part aimed at the audience at home, where Putin has hardened his anti-Western rhetoric in response to a wave of anti-government protests this year.
"From his choice seat at the Olympic Games Mr Putin will be closely watching the international reaction to his latest crackdown," Garry Kasparov, a liberal opposition leader and former world chess champion, wrote in the Times newspaper.
Russian dissidents in London held a small protest outside Russia's embassy ahead of the visit, shouting "Shame on Putin" and "Russia will be free".
Media mogul Rupert Murdoch, on his official Twitter account, said: "Interesting today to see if any decent protests against Putin his phony trials of dissenters. Russia even less free speech than here."
(Additional reporting by Gleb Bryanski in Moscow; Editing by Alison Williams)