Protestors fear an accident could damage the environment

Fife-based Catherine Stihler has been told by the European Parliament that the plans would have to be "of overriding public interest".

Forth Ports is considering an application to transfer oil between tankers four miles off the coast.

The proposals have led to concern over the environmental threat.

Opponents of the plan, which would see Russian crude oil transferred to larger tankers, have already complained that areas surrounding the Forth have nothing to gain from the project.

Mrs Stihler, a Labour MEP, asked the European Parliament if the Habitats Directive would rule out a planned activity like ship-to-ship oil transfer if the surrounding area contained protected species.

The written answer said: "A project or plan that will adversely affect a special area of conservation can only be carried out for imperative reasons of overriding public interest and in the absence of alternative solutions."

'Oil spillage'

Mrs Stihler said Forth Ports must now prove that this is the case.

"The risks of oil spillage in the Forth must not be overlooked, considering the company carrying out these transfers has a history of spillage," the Labour MEP said.

"The Habitats Directive creates a strict protection regime for sites of community importance and forbids any economic activity which risks the deterioration or destruction of breeding sites or resting places."

Mrs Stihler said she had petitioned the European Parliament, a move which led to an investigation into the proposals.

Forth Ports is currently examining a bid by Sunderland-based SPT Marine Services to use the Forth as a staging post to transfer crude oil around the world.