last time, they checked my wife's purse without a torch (so she could've hidden anything inside) and didn't check anything on me so i got in with two 1g edibles.
But to give an idea of how idiotic it is: Those are on the 32nd and 33rd floor. Next door is the Shangri La hotel of The Shard, where you can walk straight in and take the lift to the 31st (no scanners), and change to a lift for the 52nd floor (no scanners).
In Europe the major exceptions are Eurostar (Channel Tunnel) and the Spanish high-speed network, where the major stations are like airports, with airport-style security, airport-style departure lounges, and waiting. As I understand it, the extra security is at least partly an outcome of the Madrid terrorist bombings of 2004. Terribly self-defeating.
In France by contrast you can still arrive 2 minutes before the TGV departs.