13.—(1) If, in the case of a scheme in relation to which there is more than one employer, an event occurs in relation to one or more, but not all, of the employers, by virtue of which a debt may be treated as having arisen under section 75(1) (deficiencies in the assets) from that employer, or those employers, to the trustees or managers of the scheme, and—
(a)the last minimum funding valuation for the scheme before the applicable time showed that on the effective date of that valuation the minimum funding requirement was not met; or
(b)the last certificate under section 58 before the applicable time of the rates of contributions shown in the scheme’s schedule of contributions was given in the case mentioned in section 58(6)(b) (certificate given when minimum funding requirement appears not to be met) in respect of rates which were not calculated to secure that the scheme would meet the minimum funding requirement on or before that time; or
(c)the last certificate under section 57(1)(b) before the applicable time was such a certificate as is mentioned in section 57(2)(a) (inadequate contributions),
the trustees or managers must obtain a minimum funding valuation.
(2) Such a valuation must be obtained—
(a)in a case where the effective date of the valuation coincides with the applicable time, before the end of the period of six months beginning with that time; and
(b)otherwise, before the end of the period of three months beginning with that time.
(3) In this regulation “the applicable time” has the same meaning as in section 75(3).