Shortly after Sarah was reported missing, detectives started poring over images from cameras around Clapham Common on the night of March 3. A breakthrough came when they viewed footage from a bus camera showing two figures beside a white Vauxhall Astra. Using Automatic Number Plate Recognition technology, officers were able to trace the car’s journey. Police were also able to pinpoint his movements using cell-site analysis of his mobile phone – even though he had wiped all the data.

       Couzens was arrested on March 9 – six days after he kidnapped Sarah. Her body was discovered the following day.

       In a brief interview on arrest, he told officers he was forced to kidnap her on the orders of a foreign vice gang.

       Zoe Martin, prosecuting at London’s Westminster magistrates’ court in March, said: “He stated he had financial difficulties and he was being threatened by Eastern Europeans. He had underpaid a prostitute. As a consequence he had to deliver them another girl. If he didn’t, they would harm him and his family.”

       Couzens said he was flashed by a Mercedes with a Romanian number plate and pulled into a layby in Kent.

       “Three Eastern European men got out of the van and took [Sarah] and she was alive and well at that stage,” Ms Martin said.