Why are video versions often much shorter than film versions but shown as uncut ?

When a work is telecined from 35mm film stock to videotape the number of frames remains constant but the two types are shown at different speeds.

Film is projected at 24 frames per second, but video is played at 25 frames per second. To the eye the difference is usually imperceptible, each frame is shown for only a fraction of a second less on video. Over the course of a ninety minute feature the difference amounts to around four minutes so identical works will appear to be significantly different.

An extreme form of the effect can be seen with very early archive footage. When shown on television the action is speeded up as early films were often originally projected at slower speeds than is normal today.