Thousands of pupils face a year of lessons in hundreds of “temporary” classrooms – some of which have been there for nearly 40 years.

The revelation comes as tens of thousands of youngsters return to school after the summer break.

Figures obtained by The Argus show there are more than 200 mobile classrooms across Sussex, described by some as “sheds”.

Council chiefs said some have been there since before 1974.

Bosses admitted the situation was far from ideal and blamed a “baby boom” for its shortage of primary school places. They added they were committed to building new facilities but were limited by the financial situation.

But campaigners have warned the temporary buildings are increasingly being relied on to provide long term solutions.

East Sussex county councillor Rosalyn St Pierre, a Liberal Democrat who opposes every new planning application for mobile classrooms, said: “These sheds are not temporary and they are not mobile as some have been in place for years.

“They are cold and draughty in the winter and too hot and stuffy in the warmer months.

“What’s more, they take up valuable space on playing fields and playgrounds at a time when the public want to continue the Olympic legacy by encouraging sport and exercise in schools.

“Comfortable surroundings would help children to concentrate during the most important years of their lives. How many adults would tolerate such uncomfortable workplaces?”

Figures provided by East Sussex County Council showed almost all its 183 mobile rooms are used for teaching which means about 3,700 students are learning in rooms designed for temporary use only.

Council leader Peter Jones said: “There has been a baby boom which has meant, like many places across the country, more children are needing primary schools.

“It does not surprise me that some temporary classrooms have been in place since the 1990s.

“We have been under the cosh from previous Labour governments taking money from us to feather the nests of their mates in the north “We have been building schools and permenant extensions where we can.

“At the current time we have to be aware of the economic situation that everyone faces.”

Brighton and Hove City Council said it currently has 46 temporary classrooms, five of which have been in place since before 1974.

A city council spokesman said: “We have 31 temporary school buildings holding a total of 46 classrooms.

“This year we removed a number of huts from Westdene Primary School and one from Queen’s Park Primary school as a result of the expansions we carried out at these schools.

“An old temporary building at St Peters Infants in Portslade is due to be replaced in the next few months as part of our project to turn the school into an all through primary.”

West Sussex County Council did not provide figures by the time The Argus went to print.

However, a spokesman said the local authority was starting the new term with extra built places at 26 schools to accommodate the primary surge with more planned.

Bob Howitt, of city-based campaign group Action4Kids, said he was taught in temporary classrooms at Cottesmore primary school in Hove 40 years ago.

He added: “I went back recently and they are still there.

“The more modern structures they are using are not as bad as they used to be. They last about ten years but they are not cheap being on average about £150,000.

“It offers a quick solution. But what I’m not keen on is when they are relied on as a long-term solution because there is not any other planned alternative.”