thomas's written basis of plea stated that no plane was attached to horizon, and that he accepted there was a shortage which he was contractually obliged to make good, but he did not know how it had come about. the post office accepts that this was an unexplained shortfall case and that evidence from horizon was essential to mr thomas's case. mr thomas has stated he was having problems with horizon, in particular his online banking report showed several transactions with a nail amount. these were occasions when he paid money to a customer, but the system did not record the value of that transaction. this led to losses, so he altered the cash on hand figures to balance the accounts. in his interview on percussion, mrthomas accounts. in his interview on percussion, mr thomas of the alleged loss was due to mistakes in horizon and that he did not understand the system. he had made 13 calls to the