The Sovereign Grant needs to be scrapped and the monarchy funded through proper annual budgeting, in line with the normal processes used for funding all other public bodies.
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The Sovereign Grant is a nonsensical way to fund any public body. The funds come from the Treasury but are linked to the profits of the Crown Estate. There is a 'ratchet' clause that means once the Grant has gone up it can't go back down.
The result has been a massive increase in the grant over the past ten years, while public services are cut and jobs lost. The monarchy should be funded on the basis of need and budgets should be scrutinised and set annually, as they are for other institutions.