IN THE end, overhauling the No side was just too big a task for the Yes campaign.

When a late surge in the Yes vote brought the two sides within touching distance, No brought out its big guns and made sure of victory.

It looked very comfortable for No a year ago, when it had a 19-point lead in our polling. That gap narrowed for a few months then settled down in the low to mid teens.

But one figure stood out. A year ago, an already high 6 per cent of over-16s in Scotland said they were certain to vote, and a further 14 per cent were "very likely" to vote. This pointed to the likelihood of a high turnout.

That figure quickly rose to the low 70s, before surging to 84 per cent last month, a truly remarkable level of determination to vote, and in line with the eventual turnout. This suggested a strong recognition that the referendum was of vital importance and that people wanted to have their say.

This was confirmed by the rush to register to vote, which ended with an estimated 97 per cent of the population being on the electoral register.

In our monthly polls over the past year, we kept a close eye specifically on the voting intentions of those who said they were certain to vote. Throughout, a significant number of those "certain to vote" were also "don't knows", highlighting that for many, this has been a particularly difficult decision to make and why winning over these undecided voters in the final days of the campaign was so important.

Another important question for us was whether people felt they had enough information on which to decide. Throughout the campaign, a large number of people felt that they did not: even a few weeks ago, only a small majority said they had enough information.

This may have been inevitable given that major issues such as EU membership would have been subject to negotiation, but it also seemed that the repeated claim and counter-claim from both sides meant that they were reluctant to take politicians' statements at face value.

At the end, of course, a great deal of information about what would happen in the event of a No vote was rushed into the public domain, and this - from all three major parties - may have had a decisive influence on some voters. Gordon Brown's powerful speech on Wednesday may have swung more voters behind the Union.

The nationalist leadership has promised that this is a "once and for all" result rather than the start of a "neverendum".

So Thursday's vote marks the end of a long and sometimes bitter battle. But the unionist parties have all promised radical constitutional change, bringing new fiscal and legislative powers to Holyrood and potentially reforming the governance of the UK. There are more battles ahead and we, at TNS in Edinburgh and in London, will continue to keep our finger on the pulse of public opinion on both sides of the Border.

Tom Costley is head of TNS Scotland