Greece’s former finance minister George Papaconstantinou was allowed to walk free on Tuesday after a tribunal exonerated him over his handling of the infamous “Lagarde list” of wealthy Greeks with secret bank accounts abroad. The court – convened especially to try the former politician – also dropped felony charges against him for tampering with the document to remove the names of relatives from it. Instead he was found guilty of the lesser charge of committing a misdemeanour.

The former minister smiled as the presiding judge Nikos Passos said punishment would take the form of a one-year suspended sentence.

A 13-judge tribunal, in session for the first time since the late premier Andreas Papandreou was also tried before a special tribunal in 1991, said Papaconstantinou’s “prior life” as an upright citizen had been a mitigating factor. The 53-year-old, once the embodiment of hope and reform in Greece, had faced a life sentence if found culpable of breach of duty – the accusation made for failing to act on the list.

Standing before the panel in a dark suit, Papaconstantinou looked relieved as the judgment was read out.

“This is as close to an acquittal as would be possible in the circumstances,” a court official told the Guardian.

Papaconstantinou had been handed the list of 2,062 Greeks with holdings in the Geneva branch of HSBC by Christine Lagarde, at that time his French counterpart, for the express purpose of pursuing tax evaders.

The inventory had been stolen by a bank clerk at HSBC before being seized by French police. Three of Papaconstantinou’s relatives were discovered to be among the names, but at some point mysteriously disappeared from the list. Pasok, the socialist party under which he had served, expelled him when the revelations came to light.

But from the outset, the urbane, British-trained economist had vehemently protested his innocence. At the start of the trial a month ago, he repeated his long-held claim that he had been turned into a scapegoat by a political establishment bent on distracting public attention from the country’s economic woes.

As finance minister in late 2009, when Greece’s debt crisis erupted, Papaconstantinou was the architect of the harsh economic adjustment program that Athens was forced to enact in return for aid from the EU and International Monetary Fund. Unpopular measures, including spending cuts and tax rises, were enforced under his watch. Tax evasion remains the biggest single drain on the Greek economy. The country’s moneyed elite is frequently accused by the leftist-led government now in power of having got off scot-free while the vast majority of Greeks have been hit hard by the crisis.

Papacontantinou said he had been deliberately framed when it emerged that three of his relatives had been removed from the list after he ordered the data to be transferred from a CD containing the original information to a USB memory stick. “Why would I just remove their names, which would look so suspicious, and no one else?” he was quoted as saying in testimony delivered during the trial.

Papaconstantinou was tried in the same chamber where Papandreou was put on trial 24 years ago.