Brown: the battle cry to save Britain.

Once mocked for claiming to have saved the world after the 2008 financial crisis, former Labour prime minister Gordon Brown may now have the fate of Scotland in his hands.

For many English, Scotsman Brown is an unlikely hero.

Academic and awkward in front of the camera, he was ranked Britain’s most unpopular prime minister in half a century before he led the Labour party to its worst electoral defeat in a generation in 2010.

But in September this year, after the British political elite encountered a sudden surge in Scottish separatist support, it was 63-year-old Brown who seized the initiative to try to pull wavering Scots back behind the United Kingdom.

As Prime Minister David Cameron pondered his options in London and sterling fell after a poll showed separatists were on course to win independence, Brown took action.

With just days left before the September 18 referendum he appeared to be making British policy by announcing that laws granting further devolution to the Scottish parliament would be drafted by the time Scots celebrate the birthday of their most revered poet, Robert Burns, on January 25.

Cameron had little choice but to back him.

Then, on a gruelling series of speeches from the Highlands to Scotland’s biggest cities, Brown invoked the heroes of the Scottish Labour movement and warned of the risks from separatism to taxpayer-funded health and welfare systems - appealing to Scottish Labour voters to shun independence.

“We created a United Kingdom minimum wage, a United Kingdom public health service, a United Kingdom welfare state,” Brown told a packed meeting of Labour supporters in the Royal Concert Hall in Glasgow, Scotland’s biggest city.

“What we progressives have created over the last century, let no nationalist split asunder,” the Scot - widely respected by his countrymen as the son of a Presbyterian preacher - thundered, fists clenched, to applause and cheers.

In dozens of passionate speeches laced with anecdotes about everything from Scottish soccer to ancient Greek democracy, Brown has raised what even the fervently anti-socialist Daily Mail has described as “the battle cry to save Britain”.

Nationalists such as Nicola Sturgeon, deputy leader of the Scottish National Party, say that despite his oratory Brown failed to implement his ideas on social justice while in office first as chancellor of the exchequer and then prime minister.

Nonetheless, nationalist leader Alex Salmond has said that should the separatist “Yes” campaign win, he would seek to draw on Brown’s experience for “Team Scotland”.

As Reuters reported in June, Brown first joined the unionist campaign after raising concern that its negative tone was alienating Scottish voters.

Damian McBride, Brown’s former spokesman who remains close to the former premier, said the serious mistake was not making a positive case to Scots about remaining part of the UK.

“(Brown) was making phone calls eight, nine months ago warning that this would be much, much tighter than anyone thought,” McBride told BBC Radio.

Supported by Britain’s three main political parties, the ‘Better Together’ message has veered from warnings over the perils of secession to emotional appeals for unity.

“Countries can be lost by mistake,” Brown told reporters over lunch in London’s Westminster parliament in early June.

“Don’t allow it to become British politicians versus Scotland, which is how too easily this has been caricatured, because that simply plays into the hands of the nationalists. That’s a losing ticket.”

When Brown made the comments, all opinion polls were showing the unionists well ahead of nationalists but most surveys this month have shown the vote is now too close to call after a major swing to the independence campaign.

The polls offer only a partial picture but the fate of the United Kingdom may be decided by some half a million as yet undecided voters in the industrial towns of Scotland where few politicians rival Brown’s influence.

Many of the undecideds are Labour supporters who dislike being lectured by Conservatives such as Cameron, whose party has just one of Scotland’s 59 seats in the London parliament.

“Brown was drafted in to reassure Labour Scotland that voting No is good and they shouldn’t feel bad about it. He is there to get wavering Labour voters back on the side of the union,” said David Torrance, biographer of Alex Salmond.

Cameron’s job is on the line if he loses Scotland but he has conceded that his privileged English background and centre-right politics mean he isn’t the best person to win over Scots.

That has left the Better Together campaign largely in the hands of opposition Labour, winner of 41 Scottish seats in 2010 and the only party with the local organisation and support capable of checking the secessionist Scottish National Party.

They also have Gordon Brown, the only British politician that one Scottish nationalist source said Salmond fears.

“The No lot are worried, and the campaign has been lacklustre. Yes have been much better. But Brown was very impressive,” John Campbell, from Ayrshire in south-west Scotland, said after Brown’s speech in Glasgow.

Brown studied at the University of Edinburgh and gained a PhD on the Labour Party’s role in driving political change in Scotland. He has represented the constituency of Kirkcaldy and Cowdenbeath in southeast Scotland since 1983 when he shared a parliament office with another new Labour lawmaker, Tony Blair.

Their relationship dominated British politics as Brown, finance minister for a decade, coveted and eventually got Blair’s job as prime minister in 2007.

In many parts of the United Kingdom, Brown is a divisive figure. Admirers say he steered Britain through the global financial crisis, but his critics say he mismanaged the economy and ran up record state borrowing.

Brown refused an interview citing the intensity of the campaign but Ed Miliband, who once served as one of Brown’s advisers and succeeded him as Labour party leader, lauded Brown for showing the ‘heart of a lion’ in the unionist campaign.

Brown says Scotland’s identity and rights are best secured by being part of a union which he says must change radically if it is to survive.

Disclosing London’s timetable for granting more powers to Scotland, he told Labour supporters in Midlothian, south of Edinburgh: “These proposals are radical. They change not just Scotland but they change Britain.”

Certainly, some Scots are still to be persuaded by him.

“They became desperate when they sent a rarely seen hardly heard Labour backbencher,” Graeme Murdoch, 68, said at a Yes rally in Edinburgh, in reference to Brown. “The only reason he’s here is because everyone else has failed.”

But in London, some are now wondering whether - should he help pull it off - a Scottish “No” vote could be political redemption for the man who hankered after big international jobs like heading the IMF but could not seal a nomination.

“This may change views of him in Westminster,” McBride said. “And it may - miracles may happen - garner some respect for him with David Cameron and George Osborne about the way he has dealt with this ... and proved some strategic mastery in the process.”