Although the Scottish National Party (SNP) is not yet guaranteed to form the next government in Edinburgh, their win will cause Gordon Brown some sleepless nights as he prepares to succeed Tony Blair as British prime minister within weeks.

British Finance Minister Brown played a major role in the Scottish election campaign but saw his party relegated to the second political force in its traditional heartland for the first time since 1955.

If the centre-left SNP does manage to strike a deal with smaller parties to rule in a coalition, Brown's biggest headache will be the nationalists' push for independence.

He has said he will not work with a Scottish leader who wants to end the 300-year-old union with England and Wales, as SNP chief Alex Salmond does.

Salmond said Friday he was "anxious" to cooperate with the pro-union Brown, but the ideological differences between the two Scots are clear.

That schism -- and Labour's severe loss of support across Wales and England, where local elections were also held Thursday -- looks set to dominate the years before Britain's next general election, due by 2010 at the latest.

Salmond's most immediate concern is striking a coalition deal with other parties to secure the 65-seat majority he needs to control the parliament, which has limited powers over areas like health and education.

Many analysts predict the centre-left Liberal Democrats are the preferred junior partner, but their 16 seats would not be enough for a majority, making the two Greens and one independent lawmakers key figures.

But the Lib Dems have ruled out sharing power with the SNP if they stick to plans for a referendum on independence by 2010 and Salmond must overcome that sticking point, as parties begin behind-closed-door talks this weekend.

With limited room for mano-euvre, the Labour-Lib Dem coalition which has ruled Scotland for the last eight years could continue if the SNP fails to find a willing partner.

If no agreement on forming a new Scottish government is struck within 28 days, a new election will have to be held.

There were already signs of a first clash between London and Edinburgh Saturday after the election saw as many as 100,000 spoiled ballots, delays in postal votes and serious problems with electronic counting machines.

The British government's Scottish Secretary, Douglas Alexander, rejected Salmond's pledge to hold a wide-ranging inquiry into what went wrong in addition to a review already announced by the independent Electoral Commission.

But Salmond said his probe -- if he becomes first minister -- would question decisions made at the highest level, including by Alexander's office, which has legal responsibility for the election.

Alexander said the decision to combine the two ballot papers for the two voting methods used to elect the 129 lawmakers into one was approved by members of the Scottish Parliament.

Scottish ministers in Edinburgh also took the decision to hold the council elections on the same day, despite it having a different voting system. Critics say this confused people.