Hey all, I never found an actual trainer for infinite health for this game so I thought I'd whip one up.
It took me a couple of sleepless nights to trace the hp routine and there's probably a neater way to do it but it does the job, hope it proves useful to others.
Thief - Deadly Shadows v1.0
Infinite Items :- Ctrl+1
Infinite Cash :- Ctrl+2
Infinite HP (On) :- Ctrl+Pgup
Infinite HP (Off) :- Ctrl+Pgdn
*Notes - The Infinite HP cheat will sometimes disable some portals.
Just quicksave then load the save to enable the portal.