A magnetic force microscope has been constructed to image fluxlines in superconductors. In order to facilitate operation at low temperatures, cantilever deflections are detected with an interferometer which requires only an optical fibre in the cryostat. The design and modes of operation of the microscope are described. Room temperature AFM and MFM images are presented. The MFM results, combined with planned experimental improvements, point towards future success in imaging fluxlines. © 2003 American Institute of Physics