Explainer: Scotland's difficult route to another independence referendum

Scottish independence supporters are calling Thursday (May 6)'s election the most important in the nation's history as they vow that if they win a majority in the devolved Parliament, they will push for another referendum on breaking from the United Kingdom.

The Scottish National Party (SNP) is close to controlling the devolved Parliament - knows as Holyrood - outright in Thursday's election.

The only time the SNP has won a majority before in 2011, Britain's then-Prime Minister David Cameron...