By Richard Galpin
BBC News, Moscow
One of the most famous dissidents from the former Soviet Union, Vladimir Bukovsky, has called on Russians to take to the streets in a mass protest against their government, similar to the Orange Revolution in Ukraine almost two years ago.
Mr Bukovsky says Soviet-style repression is alive in today's Russia
Mr Bukovsky, who was imprisoned for more than a decade by the Soviet authorities for his opposition activities, was speaking during his first visit to Russia since President Vladimir Putin came to power in 2000.
"With every month it [Russia] becomes more and more like the former Soviet Union, with the return of political repression, political prisoners and even the return of the abuse of psychiatry for political repression," he told the BBC.
Mr Bukovsky flew back to Moscow from his home in the English city of Cambridge to publicise his plan to run as a candidate in presidential elections due to be held in March next year.
During his five-day visit he accused the security services of "taking over practically every sphere of government", adding it was "very painful to see the return of the old days".
But for all his strong words, Mr Bukovsky knows he does not have the physical strength to run for president.
Mr Bukovsky is still a key figure among Russian opposition groups
He is 65 years old and chain smokes. The fingers on his left hand are stained yellow with nicotine. His face is drawn.
He admitted he had found the few days in Moscow exhausting.
And he faces another even more fundamental obstacle.
It is almost certain the Election Commission will not register him as a presidential candidate because he has lived abroad since being expelled from the Soviet Union in the mid-1970s.
So at public meetings and a small rally in central Moscow he stressed he was less interested in running for president than in trying to galvanise and unite the remaining opposition groups which are still prepared to demonstrate publicly against President Putin and his policies.
"The opposition is very weak now and suppressed... and that's very bad," he says, "especially as the country is restoring elements of communism.
"We need a strong opposition otherwise the country may become very dangerous."
Having completed his first foray into Russia, Mr Bukovsky returned this week to the tranquillity of his modest home in Cambridge.
Further trips to the land of his birth depend on whether he feels he is having any impact.
But supporters of President Putin say Mr Bukovsky's campaign is a waste of time.
Many young people would like Mr Putin to remain in power
They stress how Mr Putin continues to have very high approval ratings among the Russian population, which is unusual for any leader coming to the end of a second and final term in office.
It is widely assumed that whoever Mr Putin supports as his successor will therefore win the presidential election.
"(Mr Bukovsky) has zero relevance to modern Russia because unfortunately he's kept himself out of the country," says Andronik Migranyan, a pro-Kremlin political analyst.
"I don't think he has any understanding of what's happening apart from what can be read in the newspapers. He's a forgotten man."
Mr Bukovsky knows he faces an uphill battle given Mr Putin's increasingly tight grip on power.
But he recalls an old toast they were fond of using when they were dissidents in Soviet days: "Here's to our hopeless cause."