THE only way to delete embarrassing photographs or bank information from a smartphone is to destroy it or "drop it in the Humber", a Hull technology expert has warned.
Paul Green, co-founder of repair company Stuf, was speaking after a Czech security firm managed to extract thousands of pictures including "naked selfies" from factory-wiped handsets.
He said once a picture or password was stored in a phone, it remained there forever – and only destroying the mobile would get rid of it.
Mr Green said: "You can't actually get rid of information completely.
"Once something is actually written in the memory it's still present for the life of the phone.
"There are still ways and means of getting photographs off."
With business partner Richard Hewick, Mr Green runs a city centre store in South Street and another at North Point Shopping Centre in Bransholme.
The pair specialise in repairing phones and retrieving data for legitimate customers but others are much less scrupulous.
The technology expert said: "There's no way of permanently deleting something off your phone, even if you do a complete factory reset.
"People keep hold of their mobiles for, on average, eight months. They sell them onto people and that information can be dragged off.
"It's quite scary when you think about it, especially now people live and die by their smartphone. They do banking on their phones and everything like that."
Experts at cyber security firm Avast bought 20 phones on eBay and were able to access 40,000 photographs.
They included at least 750 showing women in various stages of undress, along with 250 selfies showing "what appears to be the previous owner's manhood".
There were also 1,500 family photos of children, 1,000 Google searches, 750 emails and text messages and 250 contact names and email addresses.
When it comes to deleting data, old-fashioned brute force remains the best bet.
"You have to destroy the phone and break it into component parts," he said. "Or drop it in the Humber.
"That's the only way."
