Leading emergency doctors have sounded the alarm over a popular toy which could be given to children over Christmas.

The Royal College of Emergency Medicine (RCEM) has issued a "safety flash" over water beads which are marketed as toys.

Water beads have been linked to child deaths overseas and to "serious harm" to children in the UK, the RCEM said.

They can used on their own, put in stress balls, sensory toys or art kids. They are also sold as home decor or vase fillers.

The beads start small, only a few millimetres wide, but can grow to 400 times their size in around 36 hours when exposed to liquid.

If they are swallowed when small, they can expand inside a child and cause bowel obstruction - which needs surgery to remove.

They are not visible on X-rays.

The safety alert has been issued to emergency doctors to make sure they know what to look out for while working, but the College also wants to warn parents and carers of the dangers.

The RCEM safety flash also highlights concerns about the potential for children to swallow button or coin batteries and magnets.

The College said that these gifts could pose a danger to children and vulnerable adults if swallowed.

Button and coin cell batteries can lodge in the food pipe of young children causing serious harm or death due to a chemical reaction which erodes tissue.

Indeed a Health Services Safety Investigations Body published a report in 2019 which details the death of a three-year-old girl who swallowed a coin battery without her parents knowing.

Meanwhile, a previous warning from the College highlights how children can come to severe harm after swallowing super-strong magnets.

They can be in different parts of the intestine but come together, causing injury and even leading to perforation of the bowel, which requires urgent surgery.

Dr Salwa Malik, vice president of the Royal College of Emergency Medicine, said, "Any one of these three objects could be found under your tree or in a stocking this festive season, hidden in gifts that are intended to bring joy to a child or vulnerable person, but which, if swallowed, could result in critical illness and the need for emergency medical treatment.

"As an emergency medicine doctor, I have seen parents holding their child's hand and watching over them while they lay on a bed in an Emergency Department, in need of urgent care because they have ingested one of these items.

"As a parent, I can imagine how utterly terrifying and a traumatic that would be to go through - for a mum, dad, grandma, grandpa, aunt, uncle, brother, sister and of course, the child themselves.

"Having seen the effects first hand, which can be devastating and detrimental, we are asking people to please think twice about the dangers these pose while selecting and gifting presents this season.

"We are also raising awareness within emergency departments by circulating these safety flashes to ensure our colleagues in emergency departments are aware and informed about the dangers and equipped with the best clinical guidance to treat a child, or vulnerable person should they seek help after swallowing these objects."