Russian authorities have put on trial the most vocal critic of President Vladimir Putin in what experts said was a risky attempt to shut out of politics the country’s most charismatic opposition leader.

Russia’s best known anti-corruption campaigner, lawyer Alexei Navalny, who led massive anti-Putin protests a year ago, has been charged with embezzlement. If convicted Mr. Navalny could face up to 10 years in prison.

The trial opened on Wednesday in Kirov, a provincial capital, where Mr. Navalny worked as an adviser to the governor at the time of committing the “crime” three years ago, but was immediately adjourned for a week to allow defence more time to prepare its case.

Mr. Navalny is accused of stealing 10,000 cubic metres of timber via a private company, causing a loss of 16 million roubles (about $500,000) to the regional government. He said the case was based on trumped-up charges and was intended to hand down a conviction that would disqualify him from standing in elections. Experts of the legal advocacy rights group Agora who studied the charges against Mr. Navalny at his request slammed the case as “groundless” and amounting to “persecution for his public political activities.”

A day after Mr. Navalny went on trial authorities opened a new criminal investigation against him and his brother Oleg on suspicion they had defrauded a company of 3.8 million roubles ($120,000)

Mr. Navalny first became known in Russia through his anti-corruption blog, which exposed government embezzlement, and shot to prominence with his fiery speeches at protest rallies against election fraud and Mr. Putin’s return to the presidency last year. He coined the phrase “party of crooks and thieves,” which has firmly stuck to the ruling United Russia party.

Ahead of his trial Mr. Navalny said he wanted to become Russia’s President in order to dismantle “this disgusting regime of thieves” and put in jail Mr. Putin and his friends.

Experts said the Kremlin was trying to discredit Mr. Navalny by marking him out as a “criminal.” But the attempt could backfire, they warned.

“Authorities are clearly afraid of Navalny, but jailing him would be a colossal mistake. The longer he languishes in jail, the more popular he will become,” said Henry Reznik, one of the most respected Russian lawyers.

A poll conducted last month showed that Mr Navalny’s recognition among Russians had shot up from 6 per cent two years ago to 37 per cent today.