Scotland's independence vote has received a last-minute jolt of energy as polls show a surge by the Nationalist camp, which has effectively countered a mostly downbeat 'No' campaign and picked holes in London's claims to be a responsible custodian of North Sea oil.

A week ahead of the September 18 referendum and with oil remaining a major issue, pro-Union politicians and the financial community in London have been alarmed by polls showing the Nationalists level-pegging, after months in which the 'Better Together' camp had a comfortable lead.

Leaders in industry and government have presented arguments knocking down Nationalist aspirations to a prosperous Norwegian-style state underpinned by a sovereign wealth fund that would save oil wealth for future generations.

But the arguments against-such as that Norway is at an earlier stage in its oil production and is thus not comparable, or has a more favorable demographic situation-have proved less persuasive than the 'No' camp hoped.

A significant share of voters appear deaf to the mantra heard from the earliest days of the UK oil industry: the oil is running out.

The Nationalists may not always have had logic on their side, but they have been able to argue that supposedly pro-business governments in London have used the industry as a cash cow, not least in the recent drive to cut government debt.

A dour Alistair Darling, leader of 'Better Together', told an industry gathering on September 3 that Scotland had spent more than its tax revenues in 22 of the last 23 years, demonstrating the benefits of being in the UK.

North Sea revenue 'represents something like 15% of the income that would accrue to Scotland if we would become independent - to rely so much on a revenue that is notoriously volatile is presenting a massive risk,' he said.

But Fergus Ewing, Nationalist minister for energy, enterprise and tourism in the devolved Scottish government, again highlighted a 2011 tax hike that raised the top rate of North Sea tax to 81%, and a habit of quick-fire ministerial changes that have resulted in the UK having four energy ministers in just two years.

The upstream industry has seen '16 significant tax changes in the last 10 years,' said Ewing. The number of staff at the Department of Energy and Climate Change (Decc) in charge of North Sea licensing has almost halved since 1990, compared with far greater numbers in similar roles in Norway, he added.

'Instead of working to ensure that the life of fields can be extended, the Decc department have been struggling just to stand still,' said Ewing. 'The record of successive UK governments on the two prime duties of government, taxation and regulation, has been poor.'

'Who cares more for the continuing success of this great industry than the people who live and work here - that fundamentally is also the basis and rationale of the case for Scottish independence, that we can, by using our enormous human talent and mobilizing that, achieve a better all round result for Scotland.'

With the Nationalists gaining traction, the oil industry has at times appeared reluctant to get too involved, amid worries about how individual businesses might be treated after the vote, and a variety of opinions prevailing within the industry.

BP CEO Bob Dudley warned in February of 'big uncertainties' surrounding independence and made a personal appeal for the UK to stay together. With the result looking in doubt this week BP put out a statement underlining this view and stressing the need for a 'realistic view' on North Sea potential.

Shell meanwhile has said Scotland should remain part of the UK, but has sounded almost equally worried by UK threats to leave the EU.

France's Total, which could become the UK's biggest upstream producer in the next few years as a number of other companies' fields are taken offline for redevelopment, has taken a neutral line, suggesting that independence for Scotland might not make much difference.

But if the oil industry is tepid on the issue, the financial markets that help support the industry have shown nervousness at the prospect of a 'yes' vote, with the value of the pound falling in recent days.

And many in the industry are concerned that the government, whether due to the referendum or for other reasons, is being slow to enact reforms that it has agreed to implement aimed at revamping the regulatory regime and stemming the sharp fall in North Sea output seen in recent years.

Chancellor George Osborne is due to set out the preliminary results of a review of the fiscal regime in his 'autumn statement' on December 3, while a new regulator, to be established outside Decc in the Scottish oil city of Aberdeen, is being gradually assembled.

A government-commissioned report on the future of the industry by industry leader Ian Wood met with 'a lot of enthusiasm by the oil and gas industry, that here was somebody that spoke with a lot of authority and had a lot of respect, the report came out, it said basically the obvious things that those of us that had been working over the past decade or more had been talking about [...], it said all those basic things and he said it in a good way, but have we really seen any action as a result?' Bill Transier, head of North Sea focused Endeavour International, told Platts last month.

'Some major things have to happen and have to happen quickly to make an environment for people to want to go and pursue those barrels,' he said. 'The North Sea is a tremendous petroleum system that's been there producing for over 40 years, it still has a lot left behind, but the industry itself, the government, the traditional way in which we do things over there will not allow you to use new technologies, will not allow you to get access to infrastructure. They changed the tax code on us several times, the tax code is just too high to incentivize investment.'

'You've got to look at the facts and say, here are the facts and if we don't do something dramatic fairly soon, something that I consider a national treasure for the UK [...] is going to just go away.'