[SideburnsOfDoom]

> Are there airport-style security checks in train stations London?

No, of course not. It's just not realistic, for the same reasons that you gave.

There are spot checks. It has only happened to me once, since I don't fit the profile. That also has drawbacks that you mentioned - it's far too close to racial profiling, and though it's often under the banner of "anti-terrorism", it mostly confiscates knives.

Notwithstanding the 7 July 2005 bombings, Terrorism isn't a major threat. More people die from far more mundane, accidental things.