[Stooky Bill]

ITV has its own dedicated studio at Millbank from where they ‘do’ the weather and monthly local political programmes/interviews etc. I cannot speak for the BBC.

The BBC, Sky and ITN all have their Westminster offices and studios in 4 Millbank. 

It's also home to facilities companies used by other broadcasters whenever they needed crews or studios at Westminster. At one point this was Millbank Studios owned by ITV but I'm not sure what the situation is now. In fact for a long time BBC Parliament was played out of Millbank Studios by ITV employees