Drinking water could be polluted if park-and-ride goes ahead on either of two suggested sites, it has been claimed.

Engineering specialist Dr James Rhodes fears creating a giant car park at Patcham, Brighton, may cause petrol and oil to seep into water supplies.

The former Brighton University lecturer believes such a scheme would cause irreparable damage to the environment.

Brighton and Hove City Council has proposed two possible locations in Patcham for a 900-space park-and-ride. Both are facing opposition.

One, which would require six homes to be demolished, is Patcham Court Farm, immediately south-east of the A27 and A23 junction.

The other is near the RSPCA animal shelter at Braypool, north-east of the junction.

Dr Rhodes, 65, of Larkfield Way, Patcham, said the two sites could never be approved by the Environment Agency, responsible for protecting against environmental hazards.

Underneath the sites is an aquifer, porous rock from which Southern Water extracts water.

Dr Rhodes said the area was part of the Environment Agency's inner protection zone, which extends from Old London Road beyond Braypool and from Horsdean playing fields to Waterhall Golf Course.

He has written to the council expressing his views. He thought the area was also protected by an agricultural covenant passed in 1884.

Dr Rhodes said in the American town of Bowling Green, Ohio, there had been concerns that gases coming off petrol that leaked into an aquifer created a risk of explosion.

He said: "It shows what petrol can do. It runs down into the chalk as a liquid then percolates back up again, which is a very dangerous situation.

"What I am very concerned about is if we start putting car parks which aren't by statutory law allowed in an inner protection zone, we don't really know what will happen to the water supply.

"If we are going to get climatic change with long hot summers, we are going to need all the water supplies we have. We can't destroy something like that for car parking."

Southern Water spokeswoman Paula Jackman confirmed there was a bore hole at Mill Road, Patcham, licensed to extract up to 17.5 million litres of water a day, about five per cent of Brighton's supply.

She said it would be up to the Environment Agency whether the plans could go ahead.

Rupert Clubb, Sussex area manager for the Environment Agency, said it would investigate the impact on water reserves and pollution if a planning application was made.

He said: "We may be concerned. If there is a park-and-ride, with all the care in the world it does tend to drip oil if you are using the car park over a long period. You don't want it to get into the aquifers.

"We want to make sure we are not going to damage the environment."

A council spokeswoman said no park-and-ride would be built without all issues being fully considered. Councillors voted last week to carry out further investigations of the two sites.

The spokeswoman said: "Whether it is practically possible to have park and ride on these sites will be dealt with in detail."