Subject to sections 33 and 33A below, it shall be the duty of the CMA to make a reference to its chair for the constitution of a group under Schedule 4 to the Enterprise and Regulatory Reform Act 2013 if the CMA believes that it is or may be the case—
that arrangements are in progress which, if carried into effect, will result in a merger of any two or more water enterprises; or
that such a merger has taken place otherwise than as a result of the carrying into effect of arrangements that have been the subject of a reference by virtue of paragraph (a) above.