The nose landing gear of the British Airways Boeing 787-8 Dreamliner retracted while the aircraft was parked at Stand 583 at London Heathrow Airport (LHR/EGLL). The aircraft was on stand being prepared for a cargo flight to Frankfurt (BA906). A ground maintenance team was working to address three fault messages associated with the Nose Landing Gear (NLG) doors while the flight crew prepared the aircraft for the flight. The Dispatch Deviation Guide confirmed that rectification of the defects could be deferred to a later date providing the landing gear was recycled to confirm the NLG doors functioned correctly. To prevent the landing gear from retracting when up was selected, the landing gear downlock pins were fitted. However, when the lead engineer selected the landing gear lever to up, the NLG retracted. The aircraft’s nose struck the ground causing significant damage to the lower front section of the aircraft and inflicting minor injuries on the co-pilot and one of the cargo loading team. The NLG downlock pin had inadvertently been inserted in the downlock link assembly apex pin bore instead of the downlock pin hole. The design of the aircraft nose landing gear downlock assembly created an opportunity for error when inserting the NLG locking pin, with two holes located so close together that the pin could be inadvertently inserted in the incorrect location. A Service Bulletin and Airworthiness Directive was available that would have prevented the accident, but this had not yet been completed on G-ZBJB. AAIB Conclusions: The aircraft NLG retracted on the ground when the landing gear selection lever was selected to up as part of a maintenance procedure. The NLG downlock pin had inadvertently been inserted in the downlock link assembly apex pin bore instead of the downlock pin hole. When the nose of the aircraft struck the ground, significant damage was caused to the lower front section of the aircraft and minor injuries to the co-pilot and a member of the cargo load team. The design of the aircraft nose landing gear downlock assembly created an opportunity for error when inserting the NLG locking pin, with two holes located so close together that the pin could be inadvertently inserted in the incorrect location. There were powerful auditory and tactile cues that could easily mislead someone to believe the pin was correctly inserted even when it wasn’t and there were no strong visual indications to distinguish between the correct and incorrect placements. The determination of the risk of incorrect installation of the NLG downlock pin in the manufacturer’s SB and the regulator’s AD did take account of the design of the B787 NLG and the associated probability for error. The operator’s process to embody ADs and SBs considered flight safety, airworthiness and the AD’s ‘effect’ in enhancing safety, but there was no documented evidence that health and safety risks had been fully considered. Had these risks, that were clearly highlighted in the AD and SB, been given greater significance by the operator during the embodiment process, the priority of the modification may have been escalated and avoided the decision to defer implementation to the end of the compliance period.