Citing Outlaw09 in part:
BUT this is what is not understood in Europe...UK is not part and parcel of “the Schengen Agreement” zone thus the so called "free movement of EU citizens" does not apply to UK...ALL the while UK citizens take advantage of Schengen to travel, work and reside in 26 different EU countries these days....does not quite sound right does it as it appears UK wants to eat the cake but refuses to provide the flour for the cake??.
The Schengen Zone enables cross-border travel without producing a passport (or other accepted ID). The UK opted out of the Schengen Agreement (along with Ireland IRRC) and requires EU nationals produce a passport upon arrival - I'd call that free movement with a condition.

The UK in theory can refuse entry, but I understand that is rarely exercised. It can also deport EU nationals on limited grounds.