Was that a Diamond Python? It looks a bit like that to me, not that I'm an expert; my son would give me an instant report, however, he's not here. Anyhoo, they are totally harmless - even I will let one run around me (apart from the neck) they're constrictors.
I had to be in London today. By 4.30pm my meetings were over so I wandered over to tower bridge to see Mr Blaine. It was not disappointing. The wind was getting up and he was swinging around quite merrily.