21.—(1) This regulation applies where a scheme includes requirements as to the maximum fares that may be charged for particular journeys, or for journeys of particular descriptions, and that scheme includes a mechanism under which those maximum fares are varied at least every 12 months in accordance with a formula.
(2) If the lead authority considers that the conditions in paragraph (3) are met in relation to any or all of the requirements as to maximum fares that may be charged for particular journeys, or for journeys of a particular description, which are varied in accordance with a formula the lead authority may, at any time, start a review of that formula by issuing a written review notice to relevant participating operators in accordance with paragraph (4).
(3) The conditions are that—
(a)there has, since the relevant date, been a change in market conditions which materially affects the ability of relevant participating operators, acting in a competent and efficient manner, to secure an appropriate rate of return from continuing to operate existing services in accordance with the requirements as to maximum fares specified in the scheme if the fares are varied in accordance with the formula; or
(b)the effect of the formula is no longer consistent with the local transport policies of the lead authority or of the other authority or of any of the other authorities (as the case may be) by whom the scheme is made.
(4) The review notice must propose—
(a)that the requirements as to the maximum fares that may be charged for particular journeys, or for journeys of particular descriptions, contained in the scheme, or any part of the scheme, should cease to have effect;
(b)one or more revisions to the formula referred to in paragraph (1); or
(c)replacing the formula with specified maximum fares that may be charged for particular journeys, or for journeys of particular descriptions.