High pressure causing channel loss through "Inversion"
There is high pressure over the whole of the UK at the moment, and this causes the Inversion Effect. This is causing people to be missing a single Freeview multiplex, or have terrible analogue reception on a single channel. The problem may come-and-go or last for several days.
For details, please see What is the Inversion Effect and why does it effect my Freeview TV reception?.