We present refined coordinates and proper motion data for the high proper motion (HPM) stars in the Luyten Half-Second (LHS) catalogue. The positional uncertainty in the original Luyten catalogue is typically >10" and is often >30". We have used the digital scans of the Palomar Observatory Sky Survey (POSS) I and POSS II plates to derive more accurate positions and proper motions of the objects. Out of the 4470 candidates in the LHS catalogue, 4323 objects were manually re-identified in the POSS I and POSS II scans. A small fraction of the stars were not found due to the lack of finder charts and digitized POSS II scans. The uncertainties in the revised positions are typically ~2", but can be as high as ~8" in a few cases, which is a large improvement over the original data. Cross-correlation with the Tycho-2 and Hipparcos catalogues yielded 819 candidates (with m_R_<~12). For these brighter sources, the position and proper motion data were replaced with the more accurate Tycho/Hipparcos data. In total, we have revised proper motion measurements and coordinates for 4040 stars and revised coordinates for 4330 stars. In the printed version of the paper, we present the updated coordinates and proper motion information on 528 sources which represent the high proper motion subset ({mu}>1"/yr) of the LHS catalogue. The electronic version contains the updated information on all the 4470 stars in the LHS catalogue.