With a crucial vote looming on Thursday regarding the creation of a parliamentary committee to probe potential criminal offenses in the handling of the Lagarde list of Greeks with deposits at a Swiss bank, it remained unclear late on Wednesday what the exact procedure would be following a disagreement between parties.

The likeliest scenario is the staging of three successive votes – one for each of the proposals by the coalition, leftist SYRIZA, and the Independent Greeks together with ultra-right Golden Dawn.

The coalition has proposed that only former Finance Minister Giorgos Papaconstantinou be probed in connection with the handling of the Lagarde list following the revelation by prosecutors last month that the names of three of his relatives were removed from the list.

SYRIZA wants Papaconstantinou’s successor Evangelos Venizelos, who leads socialist PASOK, to be investigated along with the former. And the two smaller opposition parties want former premiers George Papandreou and Lucas Papademos to be probed too. It is expected that, for each of the votes, MPs will be given ballot papers with the names of all four politicians and the charges they would face.

In the event that the scenario of three votes is rejected at the eleventh hour, a morning vote will probably be held on what form the evening vote will take – whether it will involve three ballot boxes being set up or four, for each of the politicians cited in the proposals. SYRIZA and other opposition parties argue that if there are separate votes for each of the proposals there would be pressure on MPs to vote along party lines.

MPs from Democratic Left, the junior coalition partner, adopted the line taken by SYRIZA on Wednesday, noting that a vote on the politicians, rather than the three proposals, would be fairer. Democratic Left MPs are expected to break from the coalition line – of only participating in the vote proposed by the coalition – and join the SYRIZA ballot, probably dropping blank votes.

Meanwhile prosecutors investigating the handling of the Lagarde list are expected to summon an aide to Yiannis Diotis, the former head of the Financial Crimes Squad (SDOE), after the latter claimed to have asked her to make a copy of a memory stick containing the list and erase the original. The prosecutors are also expected to summon an ex-employee of Papaconstantinou.