Countryside campaigners say they are against plans for a new secondary school to be built on green belt land in Harpenden.
The Hertfordshire branch of the Campaign to Protect Rural England (CPRE) has written to John Wood, Chief Executive of Hertfordshire County Council, outlining its reasons for opposing the Lower Luton Road and Common Lane site as a location.
Controversial plans for a 1,500 to 2,000 pupil secondary school were drawn up by the county council at the start of October after a report earlier this year showed evidence to suggest there will be a shortage of school places in the town between 2014 and 2015 before a shortfall peaks in 2019.
CPRE Director Kevin FitzGerald said: "We accept that a new secondary school will be needed in the area, but there are strong planning reasons for not locating it on this Batford site.
"Primarily that this part of the Green Belt is vitally important in separating Harpenden from Wheathampstead.
"Lower Luton Road and Common Lane provide a long established and clearly defined boundary to the Green Belt. The ill-defined school site would prevent a defensible boundary being created against further development in the Green Belt.
"The correct way for the county council to deal with this is through the Strategic Local Plan which is being prepared by St Albans District Council.
"There is no point in county pursuing a proposal that is unlikely to succeed when the Local Plan is examined by a Planning Inspector.
"Any proposal where there are overriding planning objections is likely to be rejected by the inspector as unsound. That is what we believe would happen in this case."
Mr FitzGerald added he urged the county council to "reconsider all other options in the best interests of residents, future school pupils, parents, and the Hertfordshire countryside, than committing to the wrong option now."