Parents in the city's most competitive school catchment area face a shortfall in places after plans for new classrooms were turned down.

The £2.57 million building for Varndean School in Balfour Road, Brighton, included a new library and IT suite as well as room for another 150 pupils.

The building was rejected by Brighton and Hove City Council's planning committee, who felt it was inappropriate.

Councillor Vanessa Brown, lead member for education, described the committee's verdict as a "huge blow".

She said the school would still take in extra pupils, although they may have to be taught in mobile classrooms. Coun Brown said the council's architects had already gone back to the drawing board to revise the plans.

The Varndean extension was supposed to ensure every child in the new, joint catchment area for the school and neighbouring Dorothy Stringer School in Loder Road, would get a place at one or the other when the new admissions system takes effect in September next year.

Parents were concerned there would not be enough places at the two schools and children who missed out in a controversial lottery decider would be sent to less popular ones elsewhere.

The review of secondary school admissions highlighted the need for extra spaces at schools in the centre of the city and the headteacher and governors of Varndean agreed that they should be provided at their school.

Council papers, published last month, reveal that if places are not provided at Varndean "there is a risk that there will be insufficient secondary places in 2008 and onwards, for children living within the Brighton area".

Planning officers last week said the "bold" design would be visible from swathes of the city but concluded that it should be recommended.

The extension would have enlarged the Balfour Road site's capacity from 1,200 to 1,350 pupils and created four extra teaching posts. Education chiefs hoped to have the extension in place by September next year.

Coun Brown said last night: "It is a shame and I was very sad to hear of the decision. The facilities would have been excellent and of great value to the school.

"We will now have to look at a different design in a different location. Our architects were working on it the day after the committee meeting.

"We are hoping to present a revised design at the September planning meeting and if all goes well want to have the extension built by the October halfterm next year.

"We will commit to taking on extra pupils, but the facilities will not be as we had hoped by the start of term. We could have to use mobile classrooms until the extension is built."

Despite planning officers recommending the approval of the scheme, only Ted Kemble, chairman of the planning subcommittee, and Lynda Hyde, vice chairwoman, voted in favour.

Coun Kemble said: "Other councillors thought that it was the wrong place and it was out of keeping with the site. I think it was a brave design."

When the scheme was first mooted in March the council said an extra 60 places could be provided using £1.9 million it had set aside for extending school capacities but it was later revealed the projected cost of the extension is £2.57 million.

The price had risen because the council's original plan to provide a block of straightforward classrooms has become a grander scheme involving computer rooms and a new library.

Was the committee right to turn down the plans? Tell us below.