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 the Presbyterian Kirk would be safe.
Federal Union would ensure the protection of Scottish manufacturers.
Federal Union made it possible to reverse the Union.