The 1707 'Union' was void from inception:

"A breached term violates a valid agreement. A destroyed founding condition goes to whether the agreement was ever validly formed at all....

...In Scotland, making the Crown unconditional was treason. In England, failing in unconditional loyalty to the Crown was treason. These aren't variations on a theme, they're mutually exclusive constitutional premises, and in 1708 the one that placed sovereignty in the community was abolished and the one that placed it in the monarch’s person was imposed in its stead...

... The very condition declared “fundamental and essential… in all time coming” was, in its underlying constitutional content, dismantled almost before the Union had been tested...

...a union founded on a condition the incorporating power then destroyed was never, on its own terms, validly formed."

Void ab initio is a Latin legal phrase meaning "null from the beginning" or "void from inception". It describes a contract, law, or transaction that a court treats as completely invalid and of no legal effect from the very moment it was created, as if it never existed.