Lib Dem rebuff forces Salmond to seek minority government

· Holyrood vote to test SNP leader's authority
· Controversy over spoiled ballot papers escalates

The following correction was printed in the Guardian's Corrections and clarifications column, Monday May 14 2007

In the article below we wrongly described the SNP's one-seat lead over Labour in the Scottish parliament as a "nationalist majority". They have 47 seats but a parliamentary majority requires 65. In the same article we misspelt the first name of Tory leader Annabel Goldie as Annabelle. The spelling error has been corrected.

Alex Salmond, the leader of the Scottish National party, plans to ask the Edinburgh parliament to elect him as first minister and head of the devolved government next Wednesday, in the first major test of his party's precarious authority.

Sources close to Mr Salmond said yesterday he had abandoned hopes of forming a majority coalition with the Liberal Democrats after they rejected offers of last-minute talks brokered by the Greens on Tuesday night.

Mr Salmond, who last Thursday led his party to an historic but narrow victory over Labour, expects to unveil a partnership deal with the Scottish Green party within days under which the Greens will support his effort to be first minister.

The deal emerged as the row over the spoiled ballot papers, which marred last week's election, escalated yesterday when it emerged that 142,000 voting papers, or 7% of all the votes cast, were spoiled. That figure was significantly higher than 100,000 estimated initially.

It also emerged that only 2% of votes for parallel local council elections were rejected. This will put Douglas Alexander, the secretary of state for Scotland, under further pressure to justify his decision to ignore evidence that putting both the list and constituency votes for the Scottish parliament could confuse voters.

Agreeing a deal with the Greens, where they expect to be free to oppose SNP policies they dislike in return for concessions on issues such as climate change, transport and wind power, would be politically significant for Mr Salmond. Although the Greens have only two MSPs at Holyrood and are too small to prevent opposition parties outvoting the SNP, Mr Salmond believes their qualified support would enable him to argue that his party is consensual, and governing in Scotland's interests.

Next Wednesday's vote will be close-run and test whether opposition parties want to provoke the parliament's first political crisis by voting as a bloc for another candidate, or will grant the SNP a chance to form a government.

Labour, which came second last Thursday by 46 seats to the SNP's 47 seats, is expected to propose its leader, Jack McConnell as first minister, while the Lib Dems, on 16 seats, will also field their leader, Nicol Stephen. The Tories, who have 17 MSPs, also plan to propose their leader, Annabel Goldie, as first minister but will not join an anti-SNP bloc on Wednesday.

Senior Labour sources confirmed they plan to fight the SNP "tooth and nail" by exploiting political divisions within nationalist ranks. Labour strategists are also poised for the possibility of a byelection involving an SNP seat: a single gain for any other party at Holyrood would erase the nationalist majority. The Lib Dems, who have ignored repeated signals from the SNP that their previously solid commitment to a referendum on independence by 2010 was up for negotiation, are expected to remain in opposition.

Meanwhile the 129 MSPs were sworn in at Holyrood yesterday morning, taking the oath of allegiance to the Queen. Seven members swore their allegiance both in English and either Gaelic, or the Scots or Doric dialects. Scotland's first Asian MSP, the nationalist Bashir Ahmad, also read his oath in Urdu standing in formal Pakistani dress. SNP sources tipped Angus Robertson, the MP for Moray, to succeed Mr Salmond as party leader in Westminster.