Black-belted Vladimir Putin locked horns on Thursday with British leader David Cameron over Syria and a crackdown on Kremlin opponents before heading for an afternoon of judo diplomacy at the Olympic Games.
Prime Minister Cameron tried to 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.
But after 45 minutes of talks in Downing Street, for which Putin put in an unusually punctual appearance, Cameron and Putin said Russia and Britain still differed over Syria.
"I look forward to taking the president to the judo but note that we will be spectators, not participants," Cameron told reporters, then the two men travelled to the Olympics.
Cameron raised the fate of female punk band, Pussy Riot, whose members are on trial in Moscow for anti-Putin lyrics, with the Russian president as part of wider talks on human rights.
In a stark illustration of the still frosty ties between Britain and Russia, Putin used his stretched, Russian-number-plated black Mercedes limousine while Cameron used his armored grey Jaguar to leave Downing Street.
The two leaders entered the Olympic judo arena together just seconds after British fighter Gemma Gibbons pulled off a shock win over the world champion to get to the final of one of the women's competitions.
A one-time judo champion in his native city of St Petersburg, Putin talked animatedly with Cameron through a translator and appeared to be explaining judo to the prime minister, who in March watched basketball with U.S. President Barack Obama in Ohio.
For the 59-year-old Kremlin leader, who revels in his hard-man image, the sight of judokas body-slamming each other on the Olympic mats offered a powerful backdrop to his talks with Cameron.
BLACK BELT PUTIN
Putin's body language was closely watched for signs about the progress of the talks on his first visit to London since 2003. His last visit to Britain was to attend the Group of Eight summit in 2005 at Gleneagles in Scotland.
In previous foreign trips, Putin has even showed off his judo skills on the mats and London Mayor Boris Johnson, who is known for his own publicity stunts, said he hoped Putin would strip off to take part.
"Oh, I hope he will take part. What is he, a dab (hand), I think that's what we want to see, stripped to the waist. We want the politicians Olympics, that's what we want," Johnson said.
But Putin, tanned and dressed in a red necktie and dark suit, appeared to be focused on the judo bout in which Russia's Tagir Khaibulaev won, sealing his place in the 100-kg men's final against Olympic champion Tuvshinbayar Naidan of Mongolia.
Putin showed little emotion and just clapped while Russians -- one even dressed in a white fur hat -- waved the Russian red, blue and white flag embossed with the two headed Russian eagle.
Russia and South Korea are currently joint top of the judo medals table with 2 gold and a bronze. Russia hadn't won a judo gold since the break-up of the Soviet Union so the London Games are by far their most successful games in judo.
Putin is facing criticism in Moscow for trying to silence dissent after members of Pussy Riot went on trial and a prominent opposition blogger, Alexei Navalny, was charged with embezzlement.
As Putin entered the prime minister's office in central London, one protester screamed: "Free Pussy Riot", which echoed across Downing Street, in reference to the band who sang out an anti-Putin punk prayer in Moscow's main cathedral.
In a letter in the Times newspaper, a dozen leading rock musicians including Jarvis Cocker urged Putin to give a fair trial to Pussy Riot, whose members face up to seven years in jail for protesting inside the Moscow cathedral.
Andrey Sidelnikov, one of a handful of protesters outside Downing Street, was wearing a "Free Pussy Riot" t-shirt.
"We don't want to see Putin in a democratic country, and we want to send a message to Cameron about supporting political prisoners in Russia," he said. "In a real democracy you can't be sent to prison for singing a song."
"Cameron must, and I think he will, talk with Putin about the Syrian problem, because Putin supports the Assad regime and gives him weapons to be used against peaceful people."
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, though diplomats say privately that there is little appetite in Western capitals for direct military involvement.
Russia, on the other hand, provides arms to Damascus and has blocked three Western resolutions calling for an increase in pressure on Assad. Putin showed little sign of shifting Russia's position.
"We made note of the fact that there are some things on which we see eye-to-eye, and we agreed to continue working to find a viable solution on that matter," Putin said through a translator.
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.