Health officials should be prepared for an increasing number of children accidentally exposed to concentrated nicotine thanks to the rising use of e-cigarettes, doctors have said.

In a letter published in the Archives of Disease in Childhood, experts said there is a danger of children coming into contact with the liquid refills for electronic cigarettes - which could cause "severe symptoms" in youngsters.

In a letter published in the journal, the experts from Good Hope Hospital in Birmingham called for enhanced safety surrounding the items.

They noted that in America there has been a "massive" rise in calls to poisons centres about e-cigarette liquid - with half the calls being about youngsters who had come into contact with the substances.

The letter comes after the medics treated a toddler who had put one of the cartridges in her mouth. While the little girl's mother had quickly retrieved the refill she was worried the youngster may have swallowed some of the liquid.

Doctors said that they tried to access information on affects of swallowing such solution but found that specific guidance on the ingestion of nicotine liquid was unavailable . They monitored the girl for a number of hours before sending her home.

"The exploratory nature of young children and the attractive packaging of refills is a dangerous combination likely to lead to a growing incidence of accidental exposure to concentrated nicotine solution," they wrote.

"The risk posed by nicotine liquid to children needs to be recognised, acknowledged and acted upon by all."