LABOUR held Paisley South with a greatly reduced majority early today when Douglas Alexander scraped home despite a big swing to the Scottish National Party.

Mr Alexander narrowly denied the SNP one of its by-election spectaculars after a campaign which never came alive. He was returned on an exceptionally low poll of under 43%, with Labour's majority slashed to only 2731 from 12,759.

Those voters who did brave cold and wet weather appeared to be making a protest against the sleaze which has enveloped Labour in Renfrewshire where neighbouring Labour MP, Tommy Graham, who is suspended, awaits his fate and where the party was forced to move against a local councillor in the run-up to polling. The contest was caused by the suicide of Gordon McMaster in the summer.

Yet another failure to capture a solid Labour seat in the urban West of Scotland frustrated the nationalists whose candidate, Ian Blackford, had repeatedly attacked Labour sleaze and his opponent's embarrassment over issues such as student tuition fees and cold weather payments.

But the SNP found it impossible to rattle Labour sufficiently to match the 19% swing the nationalists earned in Monklands East which almost ousted Labour in the 1994 by-election clash. To win Paisley South, the nationalists required 17%, but managed only 11%.

For the SNP, Paisley South goes down as another near miss.

Prime Minister Tony Blair was quick to hail Labour's win. ''This is a good result for Labour after all the predictions of defeat made before the by-election was called,'' he said.

''It is the first by-election hold for the party of government since 1989. Douglas Alexander was a splendid candidate and we fought a good campaign. The voters of Paisley South have shown their support for the new Government.''

Scottish Secretary Donald Dewar was quick to congratulate the triumphant Labour candidate. ''This is a great result,'' he said.

However, he admitted it was ''not a very inspiring contest'' because of the low turn-out.

Mr Alexander taunted his SNP opponent after Labour's victory, claiming: ''The nationalists were left with nothing to say and nowhere to go.''

The young New Labour protege of Chancellor Gordon Brown had been criticised as the invisible candidate because of the party's decison to fight a campaign without holding routine daily press conferences like the SNP and Liberal Democrats.

He insisted on stonewalling the sleaze issue and fighting on Labour's record in its first six months in office.

The disappointed SNP leader, Alex Salmond, put on a brave face and claimed a ''sensational'' night and a slap in the face for the media who, he said, had predicted that Labour would romp home.

SNP chief executive Michael Russell insisted: ''It is a great night for the SNP. This was a by-election we were told we could not get near to winning and instead the Labour Party hung on for dear life.''

He claimed that in Paisley itself and in Elderslie the SNP had won the vote but only in Johnstone, the home area of former MP Gordon McMaster, had Labour done enough to win the by-election.

SNP candidate Ian Blackford received resounding applause and said: ''This will take this country on to independence. Six months into Labour's Government it's quite clear the honeymoon is almost over.''

Mr Blackford raised the prospect of by-elections pending in Tommy Graham's constituency of Renfrewshire West and the old SNP-Labour battleground of Govan, where Mohammad Sarwar is currently under police investigation for alleged corruption.

If the suspension of both MPs led to their expulsion from the party and even from the House of Commons, then Scottish politics would reach new heights of tension in the West of Scotland.

Govan has fallen twice to the nationalists in by-elections and both times it has been regained at General Elections. The promise from all parties of a new consensus approach to Scottish politics would come under immediate strain as the SNP sought to continue its inroads into traditional Labour support.

Scottish Liberal Democrat president Jim Wallace said: ''We increased our share of the vote. I think it's better than any increase of the share of the vote that we managed to get in a Scottish by-election in the last parliament. That's very satisfactory. It is a building block.''

Tory vice-chairman Annabel Goldie, who lives just a few miles outside the constituency, also stressed that Labour had been involved in a very close shave.

She claimed that if Tony Blair could come this close to defeat within just six months of winning a General Election then anything could happen in the months and years ahead.

She said: ''While this is a personal triumph for Douglas Alexander it is a political disaster for the Labour Party that a majority of 13,000 has been reduced to less than 3000 at a time when a Labour Government is only six months old.''

Conservative candidate Ms Sheila Laidlaw put a brave face on her defeat. She told the Labour victor: ''Douglas, you have a great responsibility. The name of Paisley has been put through the mud and the mire and it is now your responsibility to make sure Paisley gets its good name back.

''And I ask the SNP to do their part to make sure the name of Paisley is admired throughout the country.''

Scottish Socialist Alliance candidate Frances Curran said the result was a humiliation for New Labour. She claimed the Scottish Socialist Alliance would make its presence felt in elections for the Scottish parliament.

q A poll in England yesterday put Labour 40% ahead of the Tories, and Labour had a near-record 55% support this week in System Three for The Herald.

Result in full

Douglas Alexander (Lab) 10,346

Ian Blackford (SNP) 7615

Eileen McCartin (Lib Dem) 2582

Sheila Laidlaw (Con) 1643

John Deighan (Pro-Life) 578

Frances Curran (Scottish Socialist Alliance, Fighting Corruption) 306

Charles McLauchlan (Independent Labour) 155

Chris Herriot (Socialist Labour) 153

Kenneth Blair (Natural Law Party) 57

Majority 2731. Turnout 42.91%.