The professor of politics at Strathclyde University has told the BBC that none of the main parties have developed any discernible momentum in the Scottish election campaign, and as a result the SNP looks likely to be two seats short of an overall majority at 63.
He has also said that despite a rise in popularity of new Scottish Labour leader Anas Sarwar, that was not translating into voters prepared to back his party on election day, with the number of MSPs returned likely to remain static at 24.
The Conservatives meanwhile could return 27 MSPs, the Scottish Greens ten and the Liberal Democrats five.
While he said there was little sign the new Alba party was gaining support, Prof Curtice’s remarks came before a new opinion poll showed increased support for smaller parties. The Panelbase survey out on Tuesday suggested significant gains for both Alex Salmond’s new party and the Scottish Greens.
Prof Curtice said four of the latest polls showed Labour trailing the Conservatives in the battle for second place “and especially so on the list vote”. He said: “Apart from Labour, on average no party's support is up by more than a point on either ballot.
"All four polls have detected a drop in SNP support on the list vote – on average by as much as four points. As a result, there is now an 11-point difference between the party's support on the constituency vote, which has also slipped by a point, and that on the regional list.”
Prof Curtice said the Greens were “proving most successful at picking up SNP support on the list”, with around one in seven SNP constituency voters backing the party with their regional vote.
“At 9 per cent, the party's average standing in the polls suggests that it could be heading for its best election performance yet,” he said. “The gap between SNP support in the constituencies and that on the list means that the party's prospects of winning an overall majority are on a knife-edge.”
He added: “The SNP could be a couple of seats short of an overall majority, though much would depend on what happened in a handful of marginal constituencies that the party might – or might not – pick up given its current level of constituency support nationally.
“However, if its share of the list vote was three points higher, that might be enough to deliver the party the two extra seats it could need for an overall majority.
“There may not have been a lot of movement in the polls so far – but even quite small movements between now and next week could make an important difference to the outcome.”
Responding to the Panelbase poll, which he described as “sensational”, Mr Salmond said Alba was on course to win seats in every region of Scotland to deliver a pro-independence “super-majority”, while the SNP had “no chance of winning list seats" in any region.