The oil would be transferred in the Firth of Forth

Campaigner Les Douglas said Fife locals were "justly outraged" by the proposals from Melbourne Marine Services.

He was speaking on the first day of a committee inquiry into the Forth plans.

The Sunderland-based firm wants to pump about 7.8 million tonnes of Russian crude oil a year between tankers anchored four miles off the coast.

'Dangerous and irresponsible'

Mr Douglas, whose wife Mary put forward a petition to the Scottish Parliament protesting against the plans, said: "It feels as if we are in the hands of a private company who are prepared to play Russian roulette with the Firth of Forth and who don't care about what happens to the environment and the beauty they destroy."

Retired businessman Linden Jarvis also submitted a petition to the parliament, calling on MSPs to debate and consider the implications of any transfers.

Mr Jarvis, a shareholder in Forth Ports, branded ship-to-ship transfers as "dangerous and irresponsible".

He fears any spillage of oil will do damage to the "beautiful and highly sensitive" Forth estuary, where the marine environment includes whales, dolphins and porpoises.

We take our role as guardians of the estuary very seriously, that's why no final decision has been made at this point in time on the project Charles Hammond Forth Ports

Members of Holyrood's Environmental and Rural Development Committee considered both petitions on Wednesday.

And Mr Jarvis told them: "It doesn't matter how great the care is, a grave danger remains and even a small spillage can cause huge damage to the environment.

"That's a big expanse of water and a lot of wildlife, that's worth taking time to stop and think about."

Forth Ports, in whose harbour authority the transfers would take place, has already produced an oil spill contingency plan.

Protected wildlife

It is currently undertaking assessment work to see if the transfers would have an impact on protected wildlife in the area.

It then has to consider whether it requires to ask the Scottish Executive for a licence for the work or not.

But when representatives from the authority appeared before the committee on Wednesday, they assured MSPs they would not allow transfers to take place unless they were satisfied of their safety.

Charles Hammond, group chief executive of Forth Ports plc, insisted: "In this particular project one thing we are clear about is we would not wish to go ahead with anything which was not inherently safe.

"We take our role as guardians of the estuary very seriously, that's why no final decision has been made at this point in time on the project."