G. W. Butcher, a retired Lieutenant Colonel and civil engineer, who reported on the collapse for the army, concluded that the failure was caused by "50% reduction in the nominal strength of the member ... entirely due to decay of the untreated timber."
Additional factors were "the decision to use two 300x75 beams bolted together for the transoms in place of a solid 300x150 member" and the lack of a "regular inspection and maintenance programme [...] by the owners of the bridge".
The army withheld Butcher's report from the 1997 inquest into Richards' death and kept its contents secret until it was published illegally on the internet by the Berrymans' lawyer, Rob Moodie.
The Berrymans claim that their fight against attempts by the Occupational Safety and Health department to prosecute them for Richards' death has led to bankruptcy and the loss of their farm.
George Butcher has now spoken publicly and said Keith Berryman admitted to him that the transoms were in poor condition, that there was visible rot in some timbers, and that he was worried about the state of the bridge.