Afghan children are dying of measles, exposure, severe malnutrition or diarrhoea

Jemima Khan

But Unicef says the approaching winter, with its harsh, freezing conditions, makes the appeal more urgent.

Unicef UK's Special Representative for Children in Conflict, Jemima Khan, joined the launch in London on Tuesday.

"We want people to take notice of the fact that as many as 100,000 more Afghan children under five will die this winter if aid does not reach them in time," she said.

"This is on top of the 300,000 who already die every year of entirely preventable causes.

"Afghan children are dying of measles, exposure, severe malnutrition or diarrhoea - a disease that could be cured with a seven pence sachet of oral rehydration salts.

"Unicef can do a great deal to prevent these deaths, but we need the public's help to do it."

Donkey convoy

Mrs Khan joined Unicef worker Hermione Youngs at the event.

The British grandmother has recently returned to the UK after leading a 10km-long donkey convoy carrying 110 tons of emergency supplies into Afghanistan.

Crisis facts

winter temperatures drop to -36C over half of Afghan children are malnourished 1 in 4 children will die before their fifth birthday every 30 minutes an Afghan mother dies giving birth

Leaves printed with the words "Winter's coming - Help the Afghan children now" were distributed to commuters encouraging them to log on to the Unicef website to make a donation.

Unicef convoys entering Afghanistan are distributing warm winter clothing and blankets to tens of thousands of children as well as providing safe drinking water in the camps, food supplements to malnourished children, and safe birthing environments for young mothers.

David Bull, executive director of Unicef UK told the BBC that nearly �25m was needed to carry out the basic emergency work but with less than a month until winter falls, the organisation has received only half that amount so far.

He said: "Our job is to help children where ever we find them but we need the money to buy the supplies and get it to them".