First, we have a BBC equilent: PBS. This is "listener/viewer sponsered" content, subsidised by our taxes, contributed to as if a charitable donation by those with too much money to understand that they are double-paying.
As for the "double-paying" part... "PBS" gets less than half its operating budget from the government. (Well, PBS gets ZERO money directly from the goverment. The Corporation for Public Broadcasting gets money from the government, then parcels it out to the various public media companies (PBS, NPR, PRI.)
And here in Oregon, Oregon Public Broadcasting gets *ZERO* state government money. It is almost entirely public donation and corporate sponsor funded. (It does still get a small amount (less than 15% of their total income) from the CPB.)
If everyone stopped donating, Public TV and Radio would effectively shut down within months.