Parking problems have lead Marlborough Town Council to object to St John’s £1.19 million sixth form centre.
At a planning meeting last night the committee decided to strongly oppose the new two-storey building, also citing road safety and overlooking neighbouring houses.
The new centre, which the school hopes will open next April, would raise pupil numbers from 1,500 to 1,700.
Coun Richard Allen said: “We’re looking at 200 students many of whom will come from outside the immediate Marlborough town area. I think we’re inviting a reduction in attractiveness in this town.
“It’s already a problem for visitors to this town to find places to park, it’s a problem for residents in this town to find place to park.
“From a basic safety and facility angle I would suggest there is far too little parking, it will cause gridlock in this town.”
A number of residents also turned up to the meeting to voice their concerns.
Bob Grice, of Cherry Orchard, said: “There are several occasions when staggered parking would prevent emergency vehicles from getting to the school let alone the houses beyond that point.
“If you have a tradesman coming to your home there is nowhere for him to park.
"If you have two cars meeting up Cherry Orchard you’re looking at 200 to 250 yards of one car reversing which is not a very clever situation in a residential area.
“It’s the implications of the parking that I think should be made clear.”
The two-storey centre will be built opposite the main entrance, next to land allocated for an all-weather pitch, and will have eight sixth form classrooms and a private study area.
Work must be completed by March next year to ensure the school does not lose the grant from the Education Funding Agency, which covers the cost of the whole project.
The application will be called in by Coun Nick Fogg and will be decided by the Eastern Area planning committee.
He said: “I went to see the nearest neighbour who was very concerned about the overlooking of her property.
“This is an entirely different issue, it’s a secondary one, but nevertheless important to the lady that lives there and I support everything about the car parking as well.
“We need to speak about this while being conscious of the value of the school to this town.”