The project would be based next to a power station at Peterhead

The company said it needed more financial incentives from the government before going ahead with the carbon capture programme.

If it is viable the scheme could be running by the end of 2009.

BP said it wanted signs of support from Chancellor Gordon Brown. The government is expected to outline measures later this year.

The proposal would see the world's first industrial-scale hydrogen power scheme based in the Aberdeenshire town.

It would generate 'carbon-free' electricity from hydrogen, reducing greenhouse gas emissions by capturing carbon dioxide (CO2) and safely storing it.

'Clear signal'

Energy firms have teamed up to investigate the feasibility of the carbon capture and storage (CCS) scheme costing hundreds of millions of pounds.

The plan has won praise from energy experts, environmental campaigners and politicians alike for pointing the way forward.

A BP spokesperson warned: "What we are looking for is a clear signal by the turn of the year that the government not only sees this as part of the solution to climate change but that it is prepared to put money behind it."

Banff and Buchan MP Alex Salmond, a supporter of the project, called for government backing, and said: "I think we have a bit of negotiation going on."

The SNP leader said: "It's the most important European energy project in the last decade."