Oxford University is facing mounting concern over plans for a £57m development near the city’s Churchill Hospital, it emerged last night.

The university is proposing to demolish the Badenoch and Richards buildings on its Old Road campus, and replace them with new medical research facilities.

But there are fears that it could lead to excessive water run-off into a brook, and threaten the Lye Valley Site of Special Scientific Interest (SSSI).

Environmentalists fear extensive development on the Churchill site in recent years, including the construction of the new cancer hospital, has already increased the risk of flooding and sewage pollution.

The university is proposing to create two giant underground tanks to store water at times of flooding. But the Environment Agency opposing is it.

Cathy Harrison, Environment Agency planning officer, said: “Large underground structures constructed below the water table may act as an obstruction to groundwater flows.”

Oxford University spokesman Matt Pickles said: “It has always been the university’s intention to install two attenuation tanks and we are confident that these will eliminate any risk of flooding on the site.”

If approval is given, work is expected to begin in October.