Uber loses licence to operate in London, will still operate while appealing

You can't hail a regular taxi in London with your phone still? Why? How do you get them? Call? Or do you have to wave your arms?

It's been 10 years since you could first do it in e.g. Stockholm with normal licensed taxis.

Edit what I mean are regular taxis, not "black cabs", "minicabs" etc. I mean the iconic taxis. If you can't hail those, why not?