We are not permitted to issue a VFR clearance (in a Class D CTR) if the vis is less than 5km and/or the cloud ceiling is less than 1500ft.
But that's not what it says in MATS Pt 1. In the corrected amended
form, it says (first sentence) that you must advise VFR flights if the vis drops below 5000 m or the ceiling is less than 1500 ft. But (second sentence) if the latter is the case and the visibility is at or above 5000 m, you
can issue a VFR clearance.