There's a lot of problems with a LIbLab agreement just now. The Labour attitude to the SNP (which isn't just that Labour are Unionist, or would lose any chance of forming a UK government without Scotland: in Scotland, SNP are the party's main opponents, and if anything are to the *left* of Labour; to many Labour people in Scotland, it was inconceivable that Labour wouldn't be in power in Holyrood, and they hate the fact that the SNP have formed a government), that's just one. There's also the attitude of a chunk of Labour to PR. This also includes a lot of Scottish Labour MPs, who would lose their sinecures if the voting system changed. Like the Tories, they think if there's a change to PR, they will never govern alone again, and governing alone is what they really want to do.