Thousands of people across Scotland may have been issued with duplicate polling cards for the independence referendum.
The admission was made by a senior counting officer as the battle for Scotland’s future entered its final hours.
Crawford Langley, who has been overseeing ballots since 1973, warned “retribution would follow” – potentially in the form of a jail sentence – for anyone tempted to vote twice.
Staff at the election office in Aberdeen, where Mr Langley is depute counting officer, have been contacted by a number of concerned voters, many of whom are students registered in more than one place.
The issue was also raised with the Press and Journal by a mother in Aberdeenshire who was concerned that her son had received two cards – one for the family home and one for his term time address in the city.
The Electoral Commission Scotland insisted last night that this was “perfectly normal”.
“It is possible that some may get two polling cards,” a spokesman said.
However, he stressed that officials were primed to look out for any issues.
A “marked register” is kept at every election or referendum, detailing each voter on the electoral roll and whether they voted.
Mr Langley said no specific safeguards would be in place at polling stations on Thursday, but insisted discrepancies would be picked up and the person involved charged with electoral fraud. That is punishable by up to one year in prison and a £5,000 fine.
He said the number of duplicate polling cards was likely to involve a very small proportion of the 4.29 million Scots registered to vote, probably in the low thousands.
He added: “We have been contacted by people saying they think they are on two registers, and asking if that is ok. I think students have a fair bit of commonsense and realise it is one person one vote.
“The bottom line is that it can be tracked that someone has voted twice, maybe not on the day, but afterwards. Retribution would follow, it is not a slap on the hand, it is a very serious offence and could mean jail time.”
A spokesman for NUS Scotland said students were told to make sure they registered at home if they were not moving into their term time accommodation before the cut-off point for the electoral roll.
He said: “I think, because it is so close to freshers week, people were advised to register in both places to make sure they got a vote.
“As a result, some may have more than one polling card, but obviously you only vote in one place.
A Yes Scotland spokesman said: “It’s obviously unfortunate that this has happened, but it’s vital that people understand that they only have one vote, regardless of how many polling cards they receive.”
Better Together declined to comment.