Hewlett Packard said Autonomy, the software firm it bought in 2011, overstated profits at one of its main British units by 81 percent in the year before it was sold in Britains biggest ever technology deal. Little over a year after the $11.7 billion acquisition, the Silicon Valley company wrote down the value of Autonomy by $8.8 billion, accusing the management of accounting irregularities. Autonomy was founded and led by British entrepreneur Mike Lynch, who has repeatedly denied the allegations. In the first specific allegation since the writedown, HP said it had refiled 2010 accounts for Autonomy Systems Limited, one of its British operating units, revising the annual revenue down by 54 percent to 81 million pounds.