Korean Air flight KE908, a Boeing 777-3B5ER (HL7782) and Icelandair flight FI454, a Boeing 757-256 (TF-FIK), suffered a ground contact accident at London-Heathrow Airport (LHR). Whilst taxing for takeoff the wingtip of KE908 collided with the rudder of FI454 which was not fully parked on its stand. The commander of the B757 turned onto the stand centreline at Stand 241 at Terminal 2B without stand guidance and did not inform the ATC ground controller that they were not fully parked, contrary to Heathrow Aeronautical Information Publication (AIP) instructions. The commander of the B777 taxied past the protruding B757 believing it to be fully parked and that the ATC clearance and green taxiway lights implied the route was clear. Previous similar incidents have occurred at Heathrow. Conclusion The collision occurred because the commander of the B777 continued to taxi past the protruding B757, believing it was fully parked and that the ATC clearance and green taxiway lights implied the route was clear. The commander of the B757 did not follow the Heathrow AIP instruction to remain on the centreline if no stand guidance is available, because his normal practice was to look for guidance after he had turned onto the stand. The initiating event was a lack of stand guidance when the B757 arrived on stand, caused by ground staff shortages. Lack of stand guidance is a common occurrence at Heathrow that all parties should continue to work together to address.