[joshua c]

a security guard at a tea shop?

kind of screams high crime area

and absolutely nothing is known about the stabber

even though he is in custody

[leaning conservative]

That was my first thought; a guard at a tea shop is not a good look for London.

[Bigg Red]

Very busy tourist area. Lots of pick-pockets.

[Winniesboy]

absolutely nothing is known about the stabber even though he is in custody

That's because he was in custody. British police never release names of an arrestee until formally charged.