A polite reminder that ATC have no say in the number of flights operated by an airline. ATC cannot request airlines remove any flights from their schedules.

ATC will impose reduced flow rates for periods of time, as corporate-wage-slave has shown above, which will cause delays.

If really poor weather has been forecast a day ahead, Heathrow Airport may either request that airlines volunteer to reduce flights, or can, in extreme weather scenarios, force airlines to remove a % of flights from their schedule (known as the HADACAB process).

For a few hours this morning we were in 'VIS2' procedures, which requires increased spacing between arrivals (see first post in this thread - https://www.flyertalk.com/forum/brit...elays-fog.html )