For planning permission the relevant legislation is s171B of the Town and Country Planning Act 1990- this confirms immunity from enforcement action after 4 years:
For council tax- I believe they don't backdate to before the time the account existed- i.e. they will only charge from the point...
I offer no defence for what has occurred but I can confirm-
Dwellings built without planning permission / not in accordance with planning permission gain a lawful status after 4 years. There is nothing the council can do about that.
Council tax in these circumstances is never backdated it’s...