As soon as Scottish and English MPs began negotiations for union in 1706 there was a debate about the two options - an ‘incorporating’ or ‘federal’ union. The following arguments were made for a federal union.
Federal union, with two separate Parliaments, meant that Scotland and England would keep hold of their national differences, and members of the Church of Scotland would be glad of a guaranteed Presbyterian Kirk.
In addition, Scots law would remain - the courts system as well as Burgh rights and Scottish customs would be untouched by English domination.
Federal union would ensure the protection of Scottish manufacturers.
Scots would be more likely to benefit from union, but if this proved not to be the case then at least federal union allowed for the possibility of reversal - the separate Scottish Parliament would be able to decide this for itself without English agreement.