The European court of human rights has condemned Russia for detaining Garry Kasparov, the former world chess champion and political activist, ahead of an opposition rally in 2007.

The ECHR, Europe’s paramount authority on human rights, said on Tuesday: “[The] deprivation of his liberty was found not to be justified for any lawful purpose.”

Kasparov was detained at Moscow’s Sheremetyevo airport on 18 May 2007 before he could board a flight to Samara to attend a rally at an EU-Russian summit.

His ticket and passport were confiscated and he was taken to a police office and questioned for five hours about whether his ticket was forged. Kasparov was barred from leaving the office and an armed officer guarded the door. As a result, he missed his flight and the rally.

The ECHR said: “While the authorities claimed they had been investigating Mr Kasparov for committing the crime of forgery, there was no evidence that any forgery had taken place, let alone that the authorities had had a reasonable suspicion that he had committed that offence.

“Given that his detention had not been lawful or justified, the court held that he had therefore also been unlawfully prevented from attending the rally.”

The Russian government had said police were carrying out an operation into counterfeit air tickets that day, and 22 people, including Kasparov, had their tickets confiscated.

Kasparov unsuccessfully tried to bring legal action in Russia in 2007 before taking his case to Strasbourg. Russia can appeal against the decision within the next three months.