POLICE have said "human error" was the reason why it took five searches of 20 The Lindens to find Tia Sharp's body.
The 12-year-old's body, wrapped up in a sheet and bin bags, lay in the loft of the house for seven days before it was discovered.
Officers searched the loft twice and, in a separate visit, a sniffer dog was taken to the house but not used in the loft.
The Met apologised to Tia's family when it became clear they had missed her body and today, after Stuart Hazell's dramatic guilty plea, one of its most senior officers blamed the mistake on human error.
Commander Neil Basu said: "While the police failure did not contribute to Tia's death, the Met deeply regrets that this error caused additional distress to Tia's family by prolonging the situation when it could have been brought to an earlier conclusion."
After Tia was reported missing on August 3 a specialist team was sent to search Christine Bicknell's house in The Lindens, New Addington.
"As is routine in missing person cases, this was an initial visit to assess the situation and briefly examine the property," said Commander Basu.
"It was not intended or considered to be a full search of the property."
The following evening officers visited the house for a second time.
Two police sergeants and two constables from Croydon checked the rooms, loft space, outbuildings and two vehicles at the address as part of the missing person investigation.
None of the officers involved were trained to conduct searches.
The court heard how there had been no obvious way, such as a ladder, of accessing the space and that when they were inside, they saw bin bags but decided they were full of clothes and did not need to be disturbed.
Another search was undertaken in the early hours of August 5.
"This involved a team of specially trained officers, consisting of one Police Sergeant and five PCs," said Commander Basu.
"They were briefed to look for evidence that could help find the 12-year-old.
"The search strategy included checking rooms that Tia had access to within the address.
The loft was checked but a systematic search was not carried out."
On August 8 the police visited the house for a fourth time. This time officers were accompanied by a search dog to "sniff areas that hadn't been searched before and were less accessible", such as under floorboards and bath panels.
The dog did not go into the loft as, Commander Basu's explained, it had been searched before and was not boarded out.
Police told the court last week that the dog had lifted his head toward the ceiling, as if to indicate it had smelt something, but it would have been "impractical" to deploy in the loft due to its size.
Two days later officers attended the house again. This time they were alerted to a smell by Christine, who claimed it was cat faeces she could not find.
An experienced officer, however, recognised the smell of a dead body. The loft was searched again and this time Tia was found "well-concealed". They also found a bag containing her clothes.
The Met began a review of the searches, focusing on the loft. It found human error on how the searches were conducted and supervised was primarily to blame rather than organisational failings.
The inexperience of the constable who searched the loft was a contributing factor, Commander Basu said.
"The PC who searched the loft and the supervising sergeant were subsequently given words of advice," he added.
"Both officers are devastated by their failure to find Tia and this case has deeply affected all those involved. The PC voluntarily decided to remove himself from search duties.
"The Met apologised to Tia's family as soon as it became apparent that her body had been missed.
"A fuller internal review of the search strategy was carried out by the Met's Counter Terrorism Protective Security Command which has responsibility for specialist search officers and staff.
"Its report confirmed that human error was the major factor in this case as opposed to training or other organisational considerations.
"However, some organisational learning points did emerge, including the need to standardise the Met selection process for Licensed Search Officers. These are being taken forward."
Following today's events at court, the police released footage of an interview with Hazell after his arrest.
Hazell is seen staring at the table as a detective asks him: "So what can you tell me about the murder of Tia Sharp, Stuart?"
There is a pause as Hazell continues to look away. He scratches his head and looks very uncomfortable before replying: "Can I have a couple of minutes with my solicitor please?"
