BUILDERS working on a hospital site in Oxford upset environmentalists by polluting a wildlife-rich pond with fuel.

Contractors admitted that 250 litres of diesel mistakenly went into a pond in a wildlife corridor running across the Churchill Hospital site, in Headington.

The Environment Agency was called in, with the RSPCA also contacted by residents, fearful of the impact on local birds.

Resident Sietske Boeles said: "The pond is in the protected wildlife corridor and the spillage will have disastrous effects on the ecology both for the wildlife corridor and the protected Lye Valley."

The diesel spilt as an oil tank was being moved. The contractors were working on the new cancer centre being built on the Churchill site.

Ms Boeles, a member of the Friends of Warneford Meadow, said the oil was first noticed by walkers.

She said: "The Environment Agency got involved and there was some damage limitation, but Friends of Warneford Meadow and local residents are very concerned the measures will not be enough to protect the local wildlife and the very sensitive ecological system.

"The 40 or so ducks and coots on the adjacent pond have disappeared.

"This is another example of the lack of care for the local ecology that the Radcliffe Trust has shown over the last 18 months."

A spokesman for the hospital said: "The Environment Agency was called in and came on site the same day and said they were happy with the procedures that had been followed. The RSPCA said that no harm had been caused to the local wildlife."

Project manager Pauline Bagnall said the construction consortium took immediate action, both to contain the spill and to absorb the oil.

She added: "In addition they contacted the Environment Agency who visited the site later that day in the afternoon.

"They pronounced they were satisfied that the correct course of action had been taken."

Last winter, residents complained about the impact of building work on the wildlife corridor.

They said important habitats were being destroyed by diggers as part of a scheme to transform the wooded area around Boundary Brook into 'parkland'.

The NHS undertook to tidy up the overgrown area on the edge of the Churchill site, clearing the brook of debris and planting wildflowers to regenerate natural grassland.