A hydrogeologist employed by Europa Oil and Gas said the risk of water contamination from a proposed exploratory drilling site in the Surrey Hills was essentially zero.

James Dodds told the public inquiry into Europa’s planning application for Bury Hill Wood there was an indirect route that would allow water from the site to reach the supply for Dorking. But he said this route was “tenuous and convoluted”.

He said the risk would be reduced by sealing the site with an impermeable membrane. This mitigation would, he said, “render the risk to essentially zero”.

A water company and some local people objected to Europa’s application because the proposed well would penetrate two aquifers.

Mr Dodds said there was no risk to water supplied to Leatherhead because there was no connection between the site and the aquifers that supplied the area. He also said a private water supply used by a local resident, who spoke on the first day of the inquiry, would not be affected.

Stephen Whales, the barrister for the Leith Hill Action Group, which opposes the application, asked what proportion of wells leaked.

Mr Dodds said: “Wells are designed not to leak. They are sealed in cement and grout. There are a number of barriers. Quantitatively, the amount of leakage, I can’t answer that.”

Mr Whales put it to him: “You don’t know do you?”

Mr Dodds said: “That’s not true. The design is that they do not leak. They are tested through the construction phase to demonstrate they do not leak. What I don’t know is a quantifiable measure of the number that leak. I don’t have that number to hand”.

The inquiry inspector, Stuart Nixon, asked how much sampling of groundwater quality would be necessary to produce a baseline before drilling started.

Mr Dodds said he would expect to see what he described as natural virgin groundwater at the site. If that was the case, three samples over four months should be adequate.

Asked what would happen if there was a pollution leak from the site, Mr Dodds said measures would be taken to stop the pollution reaching Dorking. “Ultimately it would be water treatment at the water treatment facility. I have no idea what facilities they have or whether it would be appropriate.”

This afternoon’s session also heard evidence from Europa’s landscape architect, Lisa Toyne. She said the site was in an area of managed conifer woodland. This was, she said, a crop to be harvested so the site was less sensitive than one in established broad-leaved woodland.

Opponents of the application had argued it was inappropriate because the site was in an Area of Outstanding Natural Beauty and the Green Belt.

Miss Toyne said the impact of the proposed drilling rig and equipment would have a low visual impact or none at all because the application was temporary and the effects reversible.

This morning’s evidence:

Landscape architect, Elizabeth Brown, who gave evidence for Surrey County Council, told the first day of the inquiry it would take 25 years to return the drilling site to its present appearance. But Miss Toyne gave evidence that the trees would grow back in 15 years and the bracken in 18 months-two years.

Miss Toyne will be cross-examined by opponents of the scheme tomorrow, when the inquiry continues. It is expected to finish on Friday 1^st May and the decision announced several months later.

Europa refuses to rule out production at proposed Leith Hill exploration site, inquiry told

Oil in the Surrey Hills could raise £86m in tax, Europa tells public inquiry into drilling plans

And catch up on last week’s hearings