Eco-campaigners who built a classroom powered by the sun believed they were paving the way for the future.
Instead they have been taught a valuable lesson - there is not enough sun in North London to sufficiently heat their building.
The much feted zero-carbon Living Ark classroom was opened three months ago to great fanfare.
Chill factor: The Living Ark classroom may be eco-friendly but it has proved too cold for lessons to be held in it
It boasts laudable green credentials and is made from sustainable wood, sheep’s wool and soil. The roof is made of mud and grass and it has its own ‘rain pod’ and solar panels.
But there is snag - its solar panels only provide enough energy to power a few lightbulbs.
As a result the classroom is bitterly cold and uninhabitable for lessons.
Parents have branded it ‘useless’, an ‘expensive piece of wood’ and a ‘great idea for the Caribbean’.
The Living Ark was built at Muswell Hill Primary School, North London, at the cost of £25,000.
Local councillors, at Labour run Haringey council, who were behind the initiative, opened it with great fanfare in December as a beacon of their climate change policy.
But today a local parent at the 419-pupil school said teachers weren't allowing pupils into the classroom because it was too cold.
‘What is the point of a classroom that can’t be used when it’s a bit cold outside? My kids have been told it’s too cold for them to use as nobody can figure out how to heat it,’ said the parent, who did not want to be named.
‘This is just an expensive piece of hollowed out wood and no use to anyone. We are living in Britain, not the Caribbean.’
The ‘waste’ of money comes as councils across the country are facing a severe shortage of school places.
By 2018 they will need to find an additional 500,000 primary places due to a population surge.
Charlotte Linacre, Campaign Manager at the TaxPayers’ Alliance, accused the council of wasting money on pet projects which do not benefit pupils.
She said: ‘It’s an awful waste that so much money has been ploughed into this eco-mistake.
‘This project fails to meet the needs of staff and pupils by giving them a classroom that is most useful when the kids are on their summer holidays.
‘Lessons have to be learned at the local authority. They must stop spending taxpayers’ hard earned cash on expensive pet projects that do nothing to improve pupils’ education.
‘All this will teach kids is how poorly planned and costly local authorities projects can be.’
Lib Dem Councillor Gail Engerts said: ‘It is such a shame that, considering the fanfare, it emerges that this facility cannot be used by the children all year round.’
Headteacher Jill Hughes defended the project and said she hoped classes would be held in the classroom when the weather gets warmer.
She said: ‘We’re delighted to have the Living Ark - its a tremendous resource both for the school and the local community and is an important part of the Muswell Hill low carbon zone initiative.’
