HUNDREDS of billions of pounds worth of North Sea oil and gas revenues will be at risk if Scotland votes for independence, David Cameron will warn today as he brings the UK Cabinet north of the Border for only the third time in its history.
At a meeting in Aberdeen, ministers will agree to fast-track proposals experts say could unlock up to £200 billion in reserves over the next 20 years.
The Coalition Government will insist the windfall - which could see household energy bills drop - is only possible with the resources of a united UK.
The plans will also help safeguard the 450,000 jobs in the oil and gas industry in Britain, Downing Street believes.
But yesterday First Minister Alex Salmond accused successive Westminster governments of squandering oil and gas revenues.
Scottish ministers have also demanded an apology from Mr Cameron for his party's failure to set up a Norwegian-style oil fund to help finance future generations.
Tensions were mounting last night over the meeting, which will take place just a few miles from a meeting of the Scottish Cabinet in Portlethen.
Steven Camley's cartoon
Mr Salmond has challenged the Prime Minister to a head-to-head debate on independence while they are both in the north-east, a suggestion flatly rejected by Downing Street.
The SNP have also accused the UK Cabinet of being day-trippers to Scotland, jetting in on what they dubbed "Scare Force One" after reports that one minister would be travelling by RAF plane.
Mr Cameron is due to bring almost his entire Cabinet with him to Scotland, where they are expected to make a number of announcements.
Ministers including Defence Secretary Philip Hammond and International Development SecretaryJustine Greening are also expected to make visits across Scotland in what No 10 hopes will open up another front in the independence referendum campaign.
In Aberdeen the Prime Minister will pledge backing for the North Sea oil and gas industry - which he said would be vital to the UK's international future.
UK governments have backed the industry for decades, he will say, adding: "I promise we will continue to use the UK's broad shoulders to invest in this vital industry so we can attract businesses, create jobs, develop new skills in our young people and ensure we can compete."
Energy Secretary Ed Davey, taking a break from paternity leave to attend the Granite City meeting, said today's announcements would be good for all of the UK, help to cut prices and ensure the lights did not go out. Mr Davey is expected to sign off the next stage of an ambitious carbon capture and storage project planned for Peterhead.
The Coalition Cabinet meeting will back a new Scottish-based oil and gas regulator to oversee collaboration between investors in the North Sea, and ultimately boost the sector by £200 billion over the next 20 years. The idea is contained in a report by retired oil tycooon Sir Ian Wood to be published alongside the Cabinet meeting.
Scottish Finance Secretary John Swinney said the Scottish Government backed full implementation of Sir Ian's plans for a stronger, more effective regulatory body and told UK ministers to implement the idea swiftly. "Time is of the essence," he said.
But he added Scottish ministers could only give the industry the certainty it needed if they had the economic levers that come with independence.
At the weekend the SNP said an independent Scotland's energy department would be based in Glasgow and Aberdeen. Labour called on the SNP to set out its energy plans, saying energy policy was another example of how Scotland was "on pause".