Skerries School secondary department in Shetland, which has just three pupils and offers education from seniors one to four.
Closure will mean the pupils will be faced with a 90-minute ferry crossing to Vidlin on the Shetland mainland, then a 30-minute bus journey 23 miles to Lerwick. So they will have to board five days a week.
Skerries can be saved only if the Scottish Government intervenes. Education Secretary Michael Russell has six weeks to decide whether to call in the proposal to close the school and send the pupils to Anderson High, Lerwick, next summer.
Shetland Islands Council made the decision on the casting vote of convener Malcolm Bell after a two-and-a-half hour meeting ended in a 10-10 vote. Half the members supported closure and half backed a compromise of reducing it to a two-year school.
On Tuesday the Education And Families Committee had voted to proceed with the closure, but again only on a casting vote, by chairwoman Vaila Wishart.
At the full council meeting yesterday she said the secondary pupils at Skerries were being denied "access to a larger peer group of the same age and gender". "When it comes to health and wellbeing they need the opportunity to make friends and be part of a group in a range of situations," she said.
But North Isles councillor Gary Cleaver said shutting the school would remove parental choice. "We force people to put up and shut up, or move," he said. "I don't think that is a good option."
A majority of the 70 islanders oppose the closure. But the council has approved a plan that seeks saving of £3.268 million from education between 2013-18. Closing Skerries would achieve savings of £73,473 a year.
There is a fear that if the school closes it will herald depopulation. But councillors were told by their education officials that teaching such small numbers of pupils together did not offer them the best possible educational opportunities.