Labour Party leader Ed Miliband on the campaign trail in Edinburgh, Scotland, yesterday.

Reuters/Edinburgh

Britain promised to guarantee Scotland high levels of state funding, granting Scots greater control over healthcare spending in a last-ditch attempt to shore up support before tomorrow’s vote on independence.

With polls showing the decision on the fate of the UK is too close to call, welfare spending and the future of the revered National Health System have formed a central part of nationalist Alex Salmond’s case for secession.

In a deal brokered by former Labour prime minister Gordon Brown, the leaders of Britain’s three main political parties said they would retain the funding equation that sustains a higher level of public spending north of the border.

“People want to see change,” said the agreement, published in Scotland’s Daily Record newspaper and signed by Prime Minister David Cameron, Labour leader Ed Miliband and Liberal Democrat leader Nick Clegg.

“A No vote will deliver faster, safer and better change than separation,” the agreement said.

Cameron, whose job is on the line if Scots vote to break the United Kingdom, warned on his last visit to Scotland before tomorrow’s vote that there would be no going back and that any separation could be painful.

The leaders accept that even if Scotland votes to keep the 307-year union, the United Kingdom’s structure will have to change as the rush to grant so many powers to Scotland will provoke calls for a less centralised state from voters in England, Wales and Northern Ireland.

Swathes of voters in the former industrial heartlands of northern England and Wales depend on state welfare spending while some lawmakers in Cameron’s own party have asked already asked for England to be given more powers.

In the face of the biggest internal threat to the US since Ireland broke away nearly a century ago, Britain’s establishment - from Cameron and the City of London to soccer star David Beckham - have united in an almost panicked effort to implore Scots that the United Kingdom is “Better Together”.

“There’s no going back from this. No re-run. If Scotland votes ‘Yes’ the UK will split and we will go our separate ways forever,” Cameron, his voice at times faltering with emotion, said in Aberdeen, the centre of Scotland’s oil industry.

“Don’t think: I’m frustrated with politics right now, so I’ll walk out the door. If you don’t like me I won’t be here forever. If you don’t like this government it won’t last forever. But if you leave the UK that will be forever.”

The swift visit by Cameron, who is also grappling with what to do about militants in Syria and Iraq, drew a swift rebuttal from nationalist leader Salmond who argued Scotland had a historic opportunity to rule its own affairs. “The next time he comes to Scotland it will not be to love-bomb or engage in desperate last-minute scaremongering - and following a Yes vote it will be to engage in serious post-referendum talks,” the 59-year-old Scottish leader said.