Working at night As part of the quality assurance plan, the contract called for major work procedures to be supervised by HD staff. On the pretext of having to meet deadlines, Hui Hon regularly arranged for major work to be carried out after 7:00 pm, when the HD supervising staff had left. HD issued as many as 29 warning memos to Hui Hon demanding that they rectify this situation, but Hui Hon ignored these and continued with major work at night. One procedure which was deliberately conducted at night by Hui Hon to cover up a major problem was the construction of the bell-out. This had been rendered difficult, if not impossible, because of the soil collapses in most of the pile shafts. Hui Hon's ruse was to install permanent linings at night before the HD staff could inspect the bell-out, thus effectively depriving HD of the opportunity to verify that it had been successfully constructed. Hui Hon also took to installing reinforcement cages at night. The contract called for HD staff to measure the length of each reinforcement cage before installation to ensure that the length matched the depth of the pile shaft as reported. Where the pile shaft had not reached founding level, part of the reinforcement cage would be left sticking up above ground, and this had to be removed. If the reinforcement cages could be installed at night the entire process would escape HD monitoring. According to a witness, the excess steel removed was either used in pile capping or simply thrown into the shafts. Hui Hon further arranged for most of the concreting work to be completed well after 7:00 pm. Each time concrete was poured, HD staff were supposed to first check that the quantity of concrete delivered to the site matched the reported volume of the pile concerned. The night work ensured that the concreting of 30 out of the 36 piles escaped the supervision of HD staff.