Plazbot well said because of commercial constraints we cannot set a landing rate because we think its going to get bad, especially as in the case of this morning the met man kept saying its not going to happen! So when as this morning we have multiple go arounds and a large number of aircraft already left the holds in the TMA, we cannot straight away and declare a time we will be accepting more aircraft as you don't know how long LVO's will take to implement and how long to clear back log! We also have variables like EK saying certain aircraft has to have priority over other EK's and aircraft getting a slot but then diverting as IRVR went down too much!! It also doesn't help calling arrivals frequency from the stack bugging us for a time!!
The early morning arrival wave is timed just when fog arrives sorry......