1. A method for estimating motion in a sequence of video images comprising the steps of storing a plurality of fields of a sequence of video images, for each of a plurality of blocks of pixels in each field, testing a plurality of candidate motion vectors to determine which motion vector gives the best fit in determining the motion in the image between adjacent fields for that block, wherein a step of testing a plurality of candidate motion vectors includes the step of determining the amount of motion blur present in the image, and modifying the testing of candidate motion vectors in dependence on the thus determined motion blur.