IF Labour had any lingering doubts about its ability to fight off any challenge in Scotland, they should be dispelled by our System Three poll.

With Labour sitting on 50%, it is clearly heading for at least as strong a showing in Scotland as in 1997, and could even be within touching distance of a 50% share of the actual vote.

Using a much larger sample size than our normal monthly series allows a greater degree of accuracy in the measurement of voting intentions, reducing the normal margin of error from three to two points. As a consequence, we can also look at how the parties are doing on a regional basis with some degree of confidence.

The picture at a regional level repeats the story of Labour strength. In every region bar one, Labour is showing an increase on how it performed in 1997.

Labour goes forward to June 7 knowing that, rather than looking over its shoulders in some seats, it can perhaps even contemplate picking up more.

Indeed, three out of Scotland's top 10 marginal seats has Labour challenging in second place, and they are all held by the Liberal Democrats. If the regional pattern of support indicated by System Three were to be reproduced on polling day, then Labour would pick up all three - Tweeddale, Ettrick and Lauderdale; Caithness, Sutherland and Easter Ross; and, most significantly of all, Ross, Skye and Inverness West, the seat of LibDem leader Charles Kennedy.

The latter two seats are in the Highlands and Islands region where, traditionally, the LibDems do well.

Their targeted approach to election campaigning means that they are very good at beating off challenges in seats that they hold.

Their poor position in this poll suggests that the SNP would also pick up Argyll and Bute. There may be time to recover, as the campaign in 1997 showed it was the Liberal Democrats who benefited more than any other party from the cut-and-thrust of

electioneering.

For the Conservatives, the outlook is very bleak now in Scotland. Their vote share is dropping more sharply in the very regions where it needed to show increases to claw back some seats lost in 1997. For the second election in a row, it looks like wipe-out.

For the SNP, news of Labour's continued dominance of voting intentions will bring little cheer. The party is still on course for its second best-ever share of the vote in a UK general election yet, on the basis of its 25% in this poll, it may not be by much.

System Three gives the Scottish Socialist Party 3% of the vote across Scotland. It is the stated intention of the party to gain 100,000 votes in this election. With the level of support indicated, it might just achieve this.

As the campaign hots up in Scotland, the parties still have a lot to play for.

The overall result may not be in doubt as suggested by the polls, but there is much at stake at the margins.

Malcolm Dickson is a lecturer in politics at Strathclyde

University