The best way I can explain it is that it's putting the accent more on "free" than on "market", and it's a 14-year-old's definition of free: "You can't make me do anything! YOU'RE NOT MY DAD!"
However, I worry that the more accurate explanation is that it is a neofeudal structure cloaked in free-market terms.
The competition here is from Local Loop Unbundling [1], where the non-ISP part of BT, BT Openreach, works on the exchanges and cabinets. Rollout stats [2], compare Scotland and London for the rural/city development. There's up to 9 choices in London, I would expect iPlayer would work on all of them.
http://en.wikipedia.org/wiki/Internet_in_the_United_Kingdom#... https://www.samknows.com/broadband/statistics/regional