Possible post-poll options in UK

With all the main opinion polls predicting no party winning a majority in Britain's general election, the stage is set for complex negotiations that could result in four core scenarios. Informal talks are expected to start as early as today once results are in.
The four results of the election that are seen as the most likely by pollsters are the following:

1. Conservative-Liberal Democrat coalition: 
A late boost for the Conservatives and a better-than-expected result for the under-pressure Liberal Democrats could bring the current government line-up back under Prime Minister David Cameron. If the numbers do not add up to the required 326-seat majority, the Conservatives could also reach out to the Democratic Unionist Party from Northern Ireland.

2. Conservative minority: 
A more flexible option for Cameron could see the Conservatives going it alone if they end up winning the most seats but then cannot easily put together a multi-party coalition. Like the Labour version of this scenario, a minority government could spell instability even if it is backed up by a formal agreement as it would leave the Conservatives prey to shifting political sands.

3. Labour-Liberal Democrat coalition: 
Not a front-runner but things could change quickly in the night between Thursday and Friday, particularly if Liberal Democrat leader Nick Clegg loses his seat. While Clegg is seen as pro-Conservative, several senior members of the party and many of the rank and file are closer to the centre-left of Labour leader Ed Miliband who would then be the new prime minister. Smaller left-wing parties like the Social Democratic and Labour Party in Northern Ireland and the Green Party could be brought into this arrangement.

4. Labour minority: 
Miliband has ruled out any post-election "deal" with the Scottish National Party even though they would be a natural centre-left ally, citing his opposition to their claim for independence. Miliband has left open the option of the SNP voting to support a Labour minority government if they so wish. Conservatives have warned this means that Labour would be "held to ransom" by the SNP.