PA28 pilot on base entry; under Tower control; experienced a NMAC with a Cessna in the DPA traffic pattern. The Cessna pilot; with the PA28 insight; turned base and final inside the PA28 forcing a go-around.

Narrative

I was on approach to DPA in West Chicago; IL flying under orders from the Control Tower. I was asked to report 2 miles northeast on base for Runway 28. At about 3 miles northeast of the field the Tower request that I squawk IDENT which I did. At that point the Tower cleared me to land on 28. As I continued the base leg; the Tower called me out as traffic to a Cessna on the right downwind to 28. I don't recall the Cessna responding that they had me in sight. Abeam Runway 28; I turned right to my final approach (about 1 1/2 miles from the runway) and saw the Cessna on right downwind. Between this point and approximately 1 mile from the runway; the Cessna; without being instructed to do so by the Tower; suddenly turned base; then quickly turned to final right in front of me. I estimate that he was at my altitude; approximately 1;400 FT and only about 200 FT in front of me. (I was able to easily read the tail number and see the pilot in the cockpit!). I immediately slowed down to avoid a collision and pulled up slightly in preparation for a go-around. At this point the Tower again asked the Cessna if he had me in sight and also confirmed that I was clear to land. I reported to the Tower that the Cessna cut me off and that I was climbing for a go-around. She (the Tower Controller) apologized and approved my go-around; called out the traffic I was to follow on right downwind (which I reported as in sight) and eventually landed without incident. While this was close; I never felt in danger of a collision since I had the Cessna in sight at all times. I also want to make it as clear as possible that I do NOT fault the Tower Controller for this incident. I later called the Tower and talked to her about the incident and reiterated that I do not blame her for what happened. She reported that they've had issues with this Cessna pilot in the past.