The system is essentially the same, single member constituencies based on winner takes all, first past the post, however you want to call it - whoever gets the most votes in the district wins the seat and everybody else gets nothing. The difference is that somehow in Britain the smaller parties have been able to make a bit more headway, thanks to history perhaps, or the existence of several nations (and hence national parties) inside the UK.

Another factor might be that with a parliamentary system, where the executive is determined by the balance of power in the legislative (unlike the US), parties are at least somewhat stronger, so there's less room for individualism inside a party, and hence a stronger incentive to join a separate party if you don't agree with the majority of your party.

The SNP and Conservatives both seem to have reaped the benefits of demonizing the other - making Scots feel that only a SNP vote could keep the Conservatives out of power, and making the English feel that only a Conservative vote would keep the SNP from dominating the whole UK by holding the swing votes needed to give Labour a majority.

The Lib Dems were always going to lose half or more of their seats - last time around they joined the coalition with the Conservatives, annoying the large part of their voters who are pretty left-wing, and made it worse by abandoning some prominent election promises, especially on university tuition fees. But they were expected to end with 25 or 30 seats, not 8.

As for independence - the Scots rejected independence less than a year ago in the referendum. There won't be a second one immediately, and there won't be independence without a referendum. But there's almost certainly going to be a UK-wide referendum in 2017 on leaving the EU, and if the "yes" camp should win that, it's very likely that Scotland would promptly vote to secede and stay in the EU. There may be other excuses the SNP could use for a second referendum - and after yesterday's election, I wouldn't be surprised if the pro-independence camp gains enough votes to win.