To hear Vladimir Putin tell it, he works like a "galley slave", pouring blood, sweat and tears into toiling for the Russian people with little personal gain in return. Yet according to a new report by some of his harshest critics, Putin may be the richest "slave" in the world, reaping official perks as the powerful leader of a country with a long history of enriching its omnipotent tsars. Watches in white gold, yachts decked out in the plushest of drapery and at least one flying toilet worth US$75,000 are among the presidential perks detailed by Boris Nemtsov, a former deputy prime minister turned Putin critic, and his co-author Leonid Martynyuk, a member of the opposition Solidarity movement, in a report released on Tuesday. "Putin has led Russia for more than 12 years," the authors write. "Losing popularity, Putin is maniacally clinging to power. It's clear why." It's not just the "fear of losing his freedom, capital and property" or the influence of his inner circle, who have grown fantastically rich under his rule, they say. "One of the most serious reasons … is the atmosphere of wealth and luxury to which he has become accustomed and which he does not want to give up." According to the authors, Putin has overseen a phenomenal expansion in the awarding of presidential perks - 20 palaces and villas, a fleet of 58 aircraft, a flotilla of yachts worth 3 billion roubles (HK$730 million), a watch collection worth 22 million roubles and top-class Mercedes. The report, ironically titled The Life of a Galley Slave , is the latest salvo in the opposition's attempt to discredit Putin as they continue to challenge the legitimacy of his return to the presidency this year. "In a country where more than 20 million people can hardly make ends meet, the luxurious life of the president is a blatant and cynical challenge to society by a limitless ruler," the authors write. With photographs of each palace, watch and aircraft, the report paints a colourful picture of the life enjoyed by Putin, who famously compared himself to a "galley slave" during a press conference in 2008. He said of his first two four-year terms as president: "All these eight years, I have laboured like a galley slave, with all my strength. I'm pleased with the results of my work." There are the columned facades of palaces outside Moscow, in the southern resort of Sochi, and dozens more around the country. On an island in the centre of Lake Valdai stands a 930-hectare estate serviced by a 1,000-strong staff that includes a "presidential church, swimming pool, two restaurants, movie theatre, bowling alley and helipad". The authors compare Putin's nearly two dozen official residences to the number held by other state rulers - two for the leaders of the United States and Germany, and three for the president of Italy. Nine of the villas were built while Putin was at the helm of the country, they note. The leader has long attempted to present an image of average Russian machismo. During a televised meeting of his participation in Russia's nationwide census in 2010, Putin appeared on a drab beige sofa in one of the two modest flats he is officially registered as owning. Putin last declared his income - US$115,000 - in December, a requirement to run in the March presidential vote, when his bank balance was US$179,612. But, the authors note, "his lifestyle can be compared to a Persian Gulf monarch or flamboyant oligarch". Putin's spokesman, Dmitry Peskov, could not be reached for comment. He has in the past called rumours of Putin's personal wealth, revealed in diplomatic cables released by WikiLeaks, "completely stupid". Nemtsov and Martynyuk say the 58 aircraft Putin has access to comprise 43 planes and 15 helicopters. One plane, an Ilyushin-96, features an US$18 million cabin fitted out by jewellers and is said to have a toilet that cost US$75,000 alone. The report lists four yachts, including the Olympia, which the authors dub "the real diamond in the Kremlin flotilla". They say the five-storey yacht features a jacuzzi and marble bathroom and costs US$50 million a year to maintain. The authors do not touch on Putin's alleged personal wealth, instead highlighting how his lifestyle was afforded by taxpayer money which they say could have been better spent on improving the lives of the country's citizens.