In relation to each financial year a major precepting authority in England must calculate the basic amount of its council tax by applying the formula—
Where the aggregate calculated (or last calculated) by the authority for the year under subsection (2) of section 42A above does not exceed that so calculated under subsection (3) of that section, the amount for item R in subsection (1) above is to be nil.
The Secretary of State must make regulations containing rules for making for any year the calculation required by item T in subsection (1) above; and the billing authorities concerned must make the calculations for any year in accordance with the rules for the time being effective (as regards the year) under the regulations.
Regulations prescribing a period for the purposes of item T in subsection (1) above may provide that, in any case where a billing authority fails to notify its calculation to the precepting authority concerned within that period, that item must be determined in the prescribed manner by such authority or authorities as may be prescribed.
The Secretary of State may by regulations do either or both of the following—