A frustrated councillor has warned that she doesn't want to see a forest of temporary classrooms as she hit out at a Department for Education decision which she says hampered plans to add a much-needed extension to a school in North Warwickshire.

Cllr Margaret Bell's (Con, Hartshill and Mancetter) comments came after being told that a rigid DfE timescale and criteria meant the rebuilding of Hartshill School on land adjacent to the existing premises in Church Road would not allow for extra classrooms or a larger dining room.

Bern Timings, school organisation and planning manager for Warwickshire County Council, told this week's meeting of the children and young people overview and scrutiny committee that the school was one of three to be rebuilt as part of a Government programme.

He said: "We did enter into conversations with the DfE around whether we could future-proof these builds because all three areas are expecting future growth. Unfortunately the DfE weren't keen to look at an expanded school delivery – they would have asked Warwickshire to pay for it as they will only deliver a replacement, a like-for-like.

"We did speak about whether we could future-proof some of the ancillary areas such as slightly larger dining spaces but unfortunately their timeline didn't allow the county council to do the necessary due diligence on those elements once the costs were known."

Cllr Bell accepted the DfE's criteria but urged the county's education chiefs to prepare for increasing numbers attending school in the next few years.

She said: "I'd like to say that the DfE has made our life even more difficult with their approach – they were absolutely adamant that they wanted to start on site in September and we all agree that the priority is that this school must be rebuilt and nothing that we do must upset that.

"However it is agreed that we need more places at Hartshill School and we will need to put an extension on. It seems ridiculous – we are having a new school built but we are already talking about the extension because that's how we have to do it.

"I don't want to see a whole forest of temporary classrooms because it is expensive and neither do I want to see children shipped out – we have children going out of county because we haven't got spaces and that's costing us money in school transport."

Mr Timings explained that it is hoped that a Hartshill School extension could be dovetailed into the back of the DfE scheme to meet the demand.

The other schools to benefit from the Government's school rebuilding programme are Kineton School and Southam College.