Colchicine is a mitotic inhibitor. It does not allow spindle fibres to be formed. Thus, condensation of chromosomes will occur and prophase will be completed. But metaphase won't be completed. The metaphase stage is characterized by all the chromosomes coming to lie at the equator with one chromatid of each chromosome connected by its kinetochore to spindle fibres from one pole and its sister chromatid connected by its kinetochore to spindle fibres from the opposite pole.