SCOTTISH Labour's griponpower seemed to be slipping away last night after another opinion poll confirmed the SNP was on course for a historic victory in the Holyrood election.

The new TNS System 3 snapshot,whichwasconductedforScottish Television,gavetheNationalists asurprisefive-pointleadin constituencies and an astonishing 11 point lead on the regional vote.

Sucharesult onMay3 would give the SNP 51 seats in the Scottish parliament and install Nationalist leader Alex Salmond as first minister.

The poll, which is consistent with other survey findings, came on the day Scottish Labour leader Jack McConnell went head-to-headwithSalmondandothersina televised debate.

Both leaders traded blows over the issues of independence, gay adoption and clashed on their commitment to Scotland.

But the Sky TV debate was overshadowed by news of another opinion poll confirming the SNP's lead over Labour.

The poll, which was commissioned latelastmonthandbasedona sample of around 1000 adults, found the SNP on 39% of the constituency vote, five ahead of Labour on 34%. The Conservatives trailed in third on 13%, with the LibDems fourth on 11%.

The regional vote was even better for the SNP, as the poll found the Nationalists on 36%, a record 11% ahead of Labour. The LibDems came third on 13%, the Tories fourth on 11%, with the Scottish Greens trailing on 6%. The SSP, which had broken through four years ago, languished on 3% A seat projection by Professor Bill Miller at Glasgow University placed the SNP at 51, up by around 24 since the 2003 Holyrood election, while Labour dropped back to 44, a loss of six seats compared with four years ago.

The findings, if reflected in the result onMay3,wouldspelltheendfor McConnellandleadtoSalmond becoming the next first minister in an SNP-led Scottish Executive.

The Nationalists would be in a position to enter into coalition with the LibDemswho,accordingtoMiller's projection, would end up with 16 seats, giving a SNP-LD partnership a majority.

Thepoll,whichwillbeunveiled tomorrow by STV ahead of their leaders' debate, is broadly in line with other snapshots that found large leads for the Nationalists.Insidersinallparties agreed the poll was significant, as TNS System 3 has tended to find Labour leads in its recent surveys.

Meanwhile, yesterday's leader debate wasmarkedbyaseriesofclashes between Salmond and McConnell, both of whom are vying to become Scotland's next first minister.

The Edinburgh event, which went on for over 90 minutes, featured three party leaders - Salmond, McConnell and the LibDems' Nicol Stephen - as well as Tory Murdo Fraser, who was standing in for Scottish leader Annabel Goldie.

All the participants fielded questions from an invited audience, which ranged from Cardinal Keith O'Brien to historian Michael Fry, but it was the exchanges between the SNP and Labour leaders that were the most lively.

At one point, the SNP leader accused McConnellofusingthesamearguments against an independence referendum as the Tories had once deployed against a devolution plebiscite.

In another exchange, Salmond challengedMcConnellfordefending Labour's record in power over the past eight years.

"When are you going to start doing all these wonderful things that you keep saying you're going to do?" demanded Salmond. McConnell retorted: "If you'd been in the Scottish parliament for the last six years ...," a dig at the SNP leader's decision to quit Holyrood.

Atanotherpointinthedebate, Salmond ridiculed Jack McConnell's mantra that Scotland is "the best small country in the world".

"If Jack really believes that Scotland is the best small country in the world, how nonsensical is it to argue that the best small country is somehow incapable of doing exactly what our neighbours everywhere else do so well?" he demanded.

McConnell also appeared to clash with Stephen, his former deputy in the ScottishExecutive,bysuggesting Labour could govern without help from the LibDems.

He raised the prospect of Labour trying to govern on an issue-by-issue basis, striking deals with various parties.

McConnell said a coalition between his party and the Liberal Democrats was "the right thing for Scotland" in 1999 and2003butthethirdparliament offered new possibilities.

"The outcome, in terms of the government of Scotland, will first of all be determined by the results," he said.

"But secondly it could be either a coalition or an effort by the largest party to win votes on a policy-by-policy, bill-by-bill basis working with different parties at different times."

TheSTVleaders'debatewillbe screened today.