I have a VPN (virtual private network) that allows me to link to a computer network in London or Southhampton, so as far as the BBC network is concerned I'm in the UK. I just watched the first couple of minutes of the program, so technically it's not a problem. I used to do the same think when living in Southwest Asia and watching HBOGO. It's all legal, and works well if you network is reasonably fast.
For those who are curious, the VPN I am using is software-based (so no hardware to buy) and costs about $35/year.