A Ryanair Boeing 737-700 (EI-SEV) contacted the tail of a parked Jet2 Boeing 737-300 (G-GDFB) as it was taxiing at East Midlands, U.K. At the time of the accident East Midlands Airport was operating under Low Visibility Procedures (LVPs). The reported Runway Visual Range (RVR) was 300 to 325 m. EI-SEV arrived from Stansted Airport (STN) and landed on runway 27 before following taxiway Alpha eastwards to the Central Apron. Due to the poor weather and their elevated position in the control tower, air traffic controllers could not see the aircraft, taxiway or apron. G-GDFB was not painting on the Controllers’ Surface Movement Radar (SMR) display. With no other information about stand occupancy available to them, ATC were unaware that S24 was occupied. Accordingly, the ground movements controller cleared EI-SEV to taxi the shortest route to S22 which was via Quebec (Q), the western entry point to the apron. The aircraft captain taxied EI-SEV as cleared, turning left from Taxiway Quebec towards Stand S22. The flight crew became aware of an aircraft parked on S24 and noted that the space available to pass behind it looked “tight”. Seeing that the parked aircraft was on its stop bar, they were reassured that there would be enough room to pass behind, provided they accurately tracked the stand taxi-lane centreline. As EI-SEV crossed behind G-GDFB the commander brought the aircraft to a slow walking pace and the co-pilot monitored the right wing tip. From his perspective it appeared to be clear, but as they overlapped EI-SEV’s winglet struck G-GDFB’s right horizontal stabiliser. The captain brought the aircraft to a halt and reported the collision to ATC. Conclusion: Due to the poor weather conditions and limitations of the SMR, EI-SEV was given an unachievable taxi clearance. The fallibility of the human eye in accurately judging relative distance at range seduced the crew into thinking that safe separation had been achieved. Less than minimum standard taxi separations existed on S20-25 but there were no published warnings, limitations or guidance to alert ATC or flight crews to the risks. Flight crew need to remain alert to the potential for consistently safe outcomes desensitising them to latent airfield hazards.