The number of children needing surgery after ingesting button batteries is rising, according to a leading paediatric surgeon.
The increase is in line with trends seen in the US where serious child ingestion accidents involving the small batteries have increased sevenfold over the past 20 years.
Paolo De Coppi from London's Great Ormond Street Hospital told Sky News: "We have seen a huge increase of children being admitted to hospital and having tremendous operations because of button batteries.
"During COVID some of the early symptoms those children had, like choking, could be misinterpreted as symptoms of COVID."
Mr De Coppi warned that these batteries, found in everyday items such as watches, hearing aids and toys, are attractive to toddlers and young children because they are shiny and small enough to fit into their mouths.
He added: "Even if they're not fully charged, swallowed batteries can cause almost immediate damage to the gullet and also sometimes to the airways.
"If the button battery gets stuck somewhere in the oesophagus it can even cause a perforation between the oesophagus and the airway."
That happened to Hollie Phillips' son, Ralphie, days before his first birthday.
"I saw him put something in his mouth and he made a strange face, kind of like he's eating a lemon for the first time," she recalls.
Hollie said she thought Ralphie had eaten a piece of cereal but within minutes he became very unwell.
"He just projectile vomited all over everywhere, but it wasn't like a sickness bug. It was like a brown/black colour blood.
"We went down for an X-ray and by the time we came back up they said to me, it is a button battery and if your son does not have surgery now, he will die very soon."
Ralphie did undergo surgery and survived the incident, but safety campaigners say more awareness is needed to avoid other children ending up in hospital.
Duracell has launched a new public health campaign that encourages parents to check for dangerous batteries in the home.
The battery manufacturer has also released a replacement battery that is covered in Bitrex, the world's most bitter substance, to stop babies and toddlers ingesting them.
Emma Hammett, CEO of First Aid for Life, said batteries mixed with saliva release a chemical found commonly in drain cleaners.
A test with a battery on a piece of meat resulted in alarming findings.
"Within 30 minutes it is singed, within an hour it is burnt, and within about an hour and a half there is actually smoke coming off it."
Mr De Coppi hopes the new campaign would help cut the risk to children by making parents fully aware how "dangerous those batteries are how quickly damage can occur".