When Becky ordered a Barbie doll for her daughter, she got a notification from delivery firm Evri saying it had arrived. There was just one problem: it was nowhere to be seen.

There was no parcel at her front door, in the Hampshire village of Twyford, and the photo she was sent of its location was not one she recognised.

Becky turned detective - and she discovered that reports of similar incidents nearby had "snowballed".

Around the corner, her neighbour Jonathan had received a similar notification. It showed a photo of a parcel of tools he was expecting - taken inside a car - but nothing had been delivered. He tried to take it up with Evri, but told BBC Panorama that "they don't respond - it's very frustrating".

With millions relying on delivery companies to send their parcels this Christmas, we have been investigating Evri, including sending a journalist undercover as a courier.