The White Paper cannot do this. Sovereignty cannot stay where it has never been. This is not just a question of the sovereignty of the Scottish people. It is also a question of whether the Act of Union created a single sovereign state or a political union between two sovereign states.
The bulk of the text of the Act of Union rehearses things which the Westminster Parliament may not do. This is not a mark of a sovereign power. The Act of Union no more transferred Scottish sovereignty to London than the Treaty of Rome transferred it to Brussels. Any government attempt to change this would be a constitutional change so big that devolution would be trivial by comparison.
House of Lords
London SW1Reuse content