From The TimeSplitters Wiki

Brick
Ammo	1/20
Fire Rate bullets per sec/cartridge time	2.2 bps, 9s
Reload Time	0.8s
Damage (per Single Shot) Head/Body/Leg	Depends greatly on distance.
Type	Other
Zoom	No
Primary Fire	Throws Brick
Secondary Fire	Throws Brick Further
Games	All

The Brick has appeared in every TimeSplitters game so far as an unlockable weapon in the Challenge: Super Smashing Great: Don't lose your bottle and used in Challenge: Avec le Brique(same challenge category with Don't Lose Your Bottle). It has a fairly short range, and it's damage is affected at how close you fire it at the enemy; close range will kill instantly, whilst a few steps back from the enemy will only take of 40%. The secondary fire shoots at a higher angle as if it were swung under-arm into the air. When aimed at a wall it will ricochet and hit the player, causing ironically large self-damage.

Weapon Tips

You can throw the brick very close to the enemy and/or if aimed at the head, it will kill instantly. It's good for a group of people, so the brick can bounce off each person.

There is also a Brick Collision Detection Glitch found in TimeSplitters: Future Perfect.