s 910 Reduction of taxable rent by the cumulative normal rental excess
(1) This section applies if a period of account of the current lessor (“L”) is one for which— (a) the taxable rent in relation to the lease is as a result of section 905 (current lessor taxed by reference to accountancy rental earnings) an amount equal to the accountancy rental earnings, and (b) there is a cumulative normal rental excess. (2) The taxable rent for the period of account is reduced by setting against it the cumulative normal rental excess (but not so as to reduce that rent below the amount of the normal rent). (3) But see section 913(3) and (4) (under which the amount of the cumulative normal rental excess which may be set against the taxable rent is limited in some circumstances).