It was the week that Westminster finally took Scotland’s choice seriously - and began to panic.
On Friday September 5, just two weeks ago, rumours began to circulate of an opinion poll to be published by a Sunday newspaper which would reveal growing support for Scottish independence.
But it was only on Saturday evening that it emerged the poll, by YouGov for the Sunday Times, put the “yes” campaign in the lead, by 51 per cent to 49 per cent.
Strictly speaking, this told us little about the likely result of the referendum. A lead of two per cent is well within the margin of error for any poll.
But the psychological impact was massive.
In the past, most supporters of Scotland’s continued membership of the United Kingdom had assumed they were going to win.
For example, a similar poll by YouGov in September last year showed 62 per cent of Scots planned to vote “no” to independence, with just 38 per cent voting “yes”.
It was assumed the gap would close as the vote drew closer - but there was no doubt what the outcome would be.
Suddenly, that assumption looked dangerously complacent.
Labour leader Ed Miliband, Conservative leader David Cameron and Liberal Democrat leader Nick Clegg swung into action.
They announced that they were scrapping questions to the Prime Minister (it went ahead but without the party leaders) and would head to Scotland to join the “no” campaign instead.
The Scottish flag was flown above Downing Street, while David Cameron urged English councils to join him in flying the Saltire - to show the Scots how much the English wanted them to stay.
And Gordon Brown weighed in to the debate, settng out plans to give the Scottish Parliament more power if Scots stayed in the UK, including some control over income tax levels and far more control over how tax raised in Scotland is spent.
He’d actually been talking about these ideas for some time, but the difference now was that all three party leaders appeared to back them.
Where did the “no” campaign go wrong?
A televised debate on August 25 between Scottish National Party leader Alex Salmond and Alistair Daring, the former Labour Chancellor leading the “no” campaign, was widely regarded as a clear victory for Mr Salmond.
In a previous debate, Mr Salmond had struggled when asked what he would do if the UK rejected his plan for an independent Scotland to share control of Sterling.
But this time, Mr Salmond reeled off a list of potential “plan B”s - leaving Mr Darling floundering (whether the alterative currency proposals made any sense or not is another matter).
Worse than that perhaps was Mr Darling’s inability to answer when Mr Salmond asked for details of measures that would be taken to create jobs in Scotland if it stayed in the union.
While the televised debate may have had an impact, the “no” campaign had deeper problems.
It concentrated almost entirely on the dangers of independence - not necessarily a bad tactic in itself, but this allowed independence campaigners to portray themselves as the only people offering a better future for Scotland. There was too little focus on the success Scotland has enjoyed as part of the union, and the even greater success it could achieve in future.
The “yes” campaign also capitalised on anti-Westminster feeling - the same sentiment that has helped Nigel Farage and UKIP make gains in England - and skillfully portrayed the unionist side of the debate as “Westminster”.
And the “no” campaign had structural problems.
Some Conservative MPs, such as Guy Opperman, the Northumberland MP whose constituency borders Scotland, were regular visitors to the country to back the “no” campaign
But David Cameron and other senior Tories largely stayed away, at least until things looked desperate. The theory was that Conservatives are so unpopular in Scotland that a visit by the Prime Minister could actually help the other side.
But there are Conservatives in Scotland.
In the 2010 general election, Scottish Tories received 412,855 votes, not that much less than the Scottish National Party, which got 491,386 votes.
Scottish Tories tend to be firm unionists. But parties need to campaign to motivate even their most hardcore supporters, whether in an election or a referendum.
And it’s easy to forget, as we see Alex Salmond on our TV screens, that Labour has as much right to be called the party of Scotland as the Scottish National Party.
Labour won 41 Scottish seats in 2010 while Mr Salmond’s SNP got only six, although the SNP comfortably won the elections to the Scottish Parliament in 2011.
Labour is a resolutely unionist party which was led until 2010 by Gordon Brown, the MP for Kirkcaldy and Cowdenbeath (and before that by Tony Blair, who represented a North East England constituency but was born and mostly raised in Scotland).
The growth in support for independence comes partly from Labour voters who have rejected their own party’s support for the union.
And some Labour MPs have privately complained that the party’s machinery in Scotland isn’t up to scratch.
Perhaps because Labour has been dominant for so long, it is lacking the basic tools needed to reach sympathetic voters, such as up-to-date lists of their names and addresses.
In a marginal seat, such a list is essential for ensuring friendly voters actually turn out. In this case, it would have been useful for canvassing sympathetic voters and ensuring they actually voted the right (from Labour’s perspective) way.
Both Mr Cameron and Mr Miliband could face a backlash from their own MPs about the way the campaign has been run.
Earlier this year, North East Labour MPs such as Phil Wilson, MP for Sedgfield, warned against promising too much to Scotland, such as control over aviation duty or income tax. They feared giving Scotland these powers would hurt the North East.
And at the time, the party leadership listened. But it threw caution to the wind and pledged to devolve significant funding powers - without any real debate - when things looked desperate.
David Cameron faces anger from some of his MPs who argue he had no right to come out in favour of Gordon Brown’s devolution plans without consulting his party or Parliament.
Whether Scotland is better off or not as a result of this referendum remains to be seen - and that’s the most important question.
But it’s already safe to say today that none of the major parties at Westminster come out of it with much credit.