I have the Uber app which I have used in the US. Do I need to do anything different for using it in London?
I had no problem using Uber in a number of countries this spring. I did not do anything special to the app, I just made sure that the credit card associated with it was one that I had set a travel alert for.
You don't have to use uber - you can use different private hire companies (like Addison Lee which is contesting some of uber's more interesting business practices, and have their own app), and you can use the Hailo app to order and pay for a real black cab, or even book them for reliable early morning pick-up.