Soon after the two policewomen died, one of the country's most wanted men, Dale Cregan, 29, gave himself up to police. Cregan had been questioned and bailed in connection with the murder of Mark Short, 23, who was shot dead in a Manchester pub in May.
Mr Short's father, David Short, 46, who had branded his son's killer "a coward", was murdered in a gun and grenade attack at his home in August. Cregan was wanted for questioning over both killings.
At a press conference on Tuesday, Sir Peter said it was one of the "darkest days" in the history of the force. He told reporters: "Clearly we are devastated today by the loss of two of our officers."
Sir Peter paid tribute to Pc Hughes, describing her as a "chatterbox" and a "great bobby" who was "always smiling". He said Pc Bone was a "calm, gentle woman" and an "excellent bobby".
Police said Pc Bone had been in the middle of planning a civil ceremony for her same-sex partnership.