A school, homes and businesses will have to be demolished under revised plans for a new runway at Heathrow, a council has revealed.
Slough Borough Council said Pippins School in Colnbrook would be closer to the runway than previously thought.
It claims changes to the M25 will also affect a local trading estate, and lead to increased congestion and pollution.
Heathrow told the BBC it will continue to “explore options” to mitigate the impact on affected facilities.
A spokesperson said the airport is almost at the end of a 10-week consultation period but “there are currently no plans to compulsory purchase Pippins School”.
They added: “We will continue to work with all community facilities close to the new boundary – including schools – to explore options for mitigating the impacts of Heathrow expansion. This will include options including a world class noise insulation package and commitments around air quality.”
Slough Borough Council, which is supportive of development and a new runway, have criticised plans in the airport’s initial consultation.
It claims that raising the runway above ground level as it crosses the M25 could have “serious impacts” on Pippins School and nearby homes because of “worsening noise and air pollution”.
The authority added in a statement that, having inspected the plans, the school and nearby houses would be likely to be part of a compulsory purchase order.
Dialogue with Heathrow was therefore needed, it claimed, to rebuild the school at another, more suitable, location.
The leader of Slough council, James Swindlehurst, said they were objecting to the wider proposals in the hope of “shaping the ideas” Heathrow were producing.
Diverting the M25 by 150 metres to the west, he claimed, could involve the loss of homes at Elbow Meadow and buildings on the Galleymead Trading Estate in Colnbrook.
He told BBC Berkshire: “At the moment, the road hugs the M25, and the M25 hugs the airport, and we want to keep it like that”.
A Public Safety Zone, which protects people against an aircraft accident on take-off or landing, would also extend over, and “seriously blight”, houses in nearby Brands Hill, the council said.
Pippins School said it would not comment until they have discussed the proposals with Heathrow.