In the UK, they can sue for libel if it runs their image through the dirt, even if it is true.
Bollocks. They certainly could sue. And then the BBC demonstrates it's true, and the case is dismissed.
Truth is the complete defence to libel. You cannot be found guilty of libel for stating a truth. Even if the BBC deliberately sets out to do a hatchet job. If it's true, it cannot be libel.