Alex Salmond has branded the UK Government "thieves" who had plundered Scotland's "black gold", as he clashed with David Cameron over the future of North Sea oil reserves.
The UK and Scots Cabinets held separate meetings a few miles from each other in the Aberdeen area, apparently by coincidence. But they remained miles apart in their rival visions for Scotland ahead of the referendum on independence in September.
Mr Cameron ducked a challenge by Mr Salmond, Scotland's First Minister, for a debate while they were in the area.
With the No camp ahead in the opinion polls, the Prime Minister judged that he would have little to gain but everything to lose from a high-profile confrontation with Mr Salmond, which might provide the 'game-changer' the Scottish National Party needs.
Mr Cameron said: "I'm the Prime Minister and I'm passionate about this issue and I hope the Scottish people choose to stay within our family."
Visiting a BP installation 150 miles east of Aberdeen, the PM argued that the industry is better supported by the "deep pockets" and "broad shoulders" of the UK economy than under independence.
"Because we are a top 10 economy we can afford the tax allowances, the investment, the long-term structure that is necessary to make sure we recover as much from the North Sea as possible," he said.
Remaining reserves are estimated at between 15 billion and 24 billion barrels of oil, and could provide up to 40 years of production.
Mr Cameron promised to fast-track proposals presented to the UK Cabinet yesterday by Sir Ian Wood, a retired businessmen asked to review how to maximise the remaining resources.
The UK Government announced that Peterhead would be the location of the world's first gas-fired carbon capture and storage (CCS) facility as part of a £100m investment in the ground-breaking technology.
Ed Davey, the Energy Secretary, denied the move was a bribe but warned that it would be "more difficult" to fund the project if Scots voted for independence.
Mr Salmond, a former energy economist, spoke of the "thieves" at the Commons as he said: "It hasn't been so much the broad shoulders of Westminster as the vast cavern in the Treasury over the last 40 years where they've accumulated massive oil and gas revenues from Scotland. The reason they want to hang on to Scotland's resources is that they've done so well out of them over the last 40 years. I think the next 40 years should be Scotland's turn."
"We are told today that North Sea oil and gas is better handled by a big country like Britain as opposed to a small country like Scotland. That's a very interesting concept for people in this part of the country, who can glance across the North Sea to Norway, a country smaller than Scotland but one which by every observation has handled its oil and gas resources better than the stewardship of Westminster. Norway has accumulated much of its revenues for a futures fund for future generations."
Scottish First Minister Alex Salmond