Mr McLeish was sworn in as first minister

And he predicted that the Falkirk West by-election, which was sparked by the resignation of rebel MP Dennis Canavan from his Westminster seat, would be a "straight fight" between Labour and the SNP.

But the SNP hit back at his claims, saying that only it could be trusted to stand up for Scotland.

On Saturday, constituency party delegates, trade unionists, MPs and MSPs gathered to confirm the appointment of Mr McLeish, who stood unopposed for the Labour leadership.

It was also a one-horse race for the position of deputy leader, with left-wing MSP Cathie Jamieson the only candidate.

Mr McLeish had been elected as the party's interim leader in a secret ballot at a meeting of MSPs and members of Labour's Scottish executive in Stirling in October.

Electoral college

The Fife MP and MSP defeated Jack McConnell by 44 votes to 36 after a two-day campaign, which was forced by the death of former First Minister Donald Dewar.

The tight timescale imposed under the Scotland Act meant Labour did not have time to ballot its full electoral college because a new first minister had to be appointed within 28 days.

After winning the initial Labour ballot, Mr McLeish became the party's candidate for the first minister's post.

He was elected later that month after defeating challenges from Scottish National Party leader John Swinney, Scottish Conservative leader David McLetchie and independent MSP Mr Canavan.

Dennis Canavan stood against Mr McLeish

However, Labour's constitution requires the leader to be chosen by the full electoral college.

After accepting the party leadership, Mr McLeish said the Falkirk West by-election was a straight fight between Labour and the SNP.

"The people of Scotland and of Falkirk know that the Nationalists would put up everyone's tax," he told party members.

"The only question is, by how much?

'Costly divorce'

"They would spend it on armies, a navy and an air force. It would not build better schools or more hospitals.

"It would only pay for the costly and unnecessary divorce they are committed to."

Mr McLeish claimed that the SNP's policy on drug smuggling was naive, divisive and "offensive" to the victims of drug crime.

And he added: "The Nationalists want this by-election to be an early Christmas present from John Swinney to William Hague."

Red card

However, the SNP hit back at the first minister, claiming that his party was following orders from London rather than defending Scotland's interests.

The party has launched a "red card" campaign accusing Labour of trying to scrap the Scottish national football team - a reference to recent comments made by Home Secretary Jack Straw.

The SNP added: "On both local and national issues, New Labour can't be trusted - they always put London's interests first."