LEAKED UK Government papers have reawakened fears England would insist on border controls with an independent Scotland.

They show that UK officials believe the action might be necessary to prevent illegal migrants travelling into the remaining part of the UK.

The Herald revealed in October that UK Government legal advice suggested an independent Scotland would have to join the euro and build checkpoints on the English border due to the Schengen agreement, which allows free travel.

The Schengen system is used by 25 European states but not Britain. Experts warn Scotland may have to join the system if applying for EU membership.

The Scottish Government insists the issue is a red herring and Scotland will simply continue as an EU member, albeit one no longer part of the rest of the UK. The Scottish Government called the advice "tired old scare stories".

Conservative leader Ruth Davidson said: "If Alex Salmond is so sure of his position, then why does he not produce the hard evidence that backs up his assertion?"

Scottish Labour's Patricia Ferguson said: "It is not good enough for SNP spokespersons to trot out the tired old claims that everyone who disagrees with them is wrong."