The SNP has overtaken Labour since the last mruk poll conducted three weeks ago. Labour was narrowly ahead of the SNP then and now the SNP has edged into the lead.

The SNP now has 38% to Labour's 34% of the constituency vote, the opposite of three weeks ago. This represents a significant improvement in the SNP's support compared with the last elections, though the race remains tight.

The other parties appear to have been squeezed.The Liberal Democrats' hope of building on their strong performance in the 2005 General Election has not been fulfilled.

Voters are again showing a willingness to cast their votes differently in UK and Scottish elections and the battle for third place looks even tighter than for first place.

It also looks likely that the new parliament will see fewer Other'' MSPs: Greens, SSP and independents.

Business support has been a battleground in this election. This is not only about winning the support of a group who are, after all, a relatively small minority in the Scottish electorate, but the credibility that business support gives a party.

It is also about impressing the wider electorate, especially middle-class voters. In the past, Conservatives commanded overwhelming business support and the reputation as economically competent.

New Labour challenged the Tories on this ground and we are now seeing the SNP challenge Labour for the pro- business mantle. The lack of middle-class support for the Conservatives shows how much Scottish politics has changed. Labour and the SNP each easily outpoll the Tories among those voters who were regarded as natural Tory voters not so very long ago.

The average picture that emerges from the series of polls over the campaign is of the SNP on around 35% in the constituency vote and 34% in the list; Labour on 31% and 30%; the Liberal Democrats on 14% in both; the Conservatives on 12% in both; the Greens around 5% on the list.

These averages combine the results of different organisations using different methods at different times but potentially remove discrepancies in any one poll.

Translating polls into seats is always hazardous but an average of the polls suggests the SNP with 49 seats and Labour 45. The Liberal Democrats could end up with 19 and the Tories fewer than 14. The Greens would end up with only two but the variation in support for the Greens makes it difficult to know. The poll confirms evidence that the SNP has a women problem'' though, of course, this might equally be described as Labour's men problem''.

Despite the swing to the SNP since the last poll there is no difference in perceptions of who would be the best First Minister. Alex Salmond retains a significant lead over Jack McConnell but that lead remains the same as before.

But there is no hiding the problem the Nationalists have when it comes to support for independence. There appears to have been a decline in support for independence over the past three weeks.

The paradox of this election is that the party of independence has seen its support rise while support for its raison d'être has fallen.

This is at least partly explained by the SNP's policy of a referendum on independence. Voting for the SNP does not automatically result in independence. However, the referendum will create problems once the election is over.

The swing to the SNP since 2003 looks set to be impressive but it is well short of that required to allow the SNP to have an overall majority.

And we should not forget the local elections. There will be far more SNP councillors in Scotland by the end of next week and far fewer Labour councillors. These elections are set to mark the final transition to multi-party politics in Scotland.

  • James Mitchell is professor of politics at Strathclyde University.