THIS is potentially one of the most complex issues which will be faced in the negotiations should there be a Yes vote for independence.
Theresa May has given a strong hint that the rest of the UK would deny Scots a UK passport. This is despite the fact that the British Border Agency advises British subjects that they can have dual nationality as long as the other country accepts dual nationality status.
It is possible that a Yes vote in Scotland will be interpreted as an anti-English vote which will mean that options like keeping a British passport will be withdrawn from Scots.
There is mixed historial precedent. Irish citizens were allowed dual nationality and keep hold of their British passports after the creation of the Irish Free State in 1922 until the British Nationality Act came into force in 1949.
More recently, when the Soviet Union broke up citizens had to hand back their old Soviet passports and choose one from just one of the new countries. Dual nationality was not available.
The only group guaranteed of keeping their British passports are those who choose to be citizens of the rest of the UK. As the successor state the rest of the UK will be most likely able to continue with the old passports.