A fifth of all child and teenager deaths in England have preventable causes such as accidents, fatal assaults, abuse or neglect, new research has shown.

Child death rates are also higher in the north than in the south of the country, and are closely linked to poverty, a series of studies found.

Each year around 5,000 infants, children and adolescents die prematurely in England and Wales.

Although the number is low relative to population size, the research authors stress that a large proportion of the deaths are preventable.

One study showed that between 2010 and 2011, 20% of deaths of children and teenagers aged 18 and under in England could have been avoided.

Preventable deaths were defined as "those in which modifiable factors may have contributed to death". Causes included accidents, suicide, deliberately-inflicted injury, abuse or neglect, and acute medical conditions.

Another paper found clear regional differences in child death rates in England and Wales. They tended to be higher in the Midlands and North than in the South and East.

The one exception was the North East, where death rates were relatively low.

Lead researcher Peter Sidebotham, from the University of Warwick, said: "What these variations in mortality tell us is that more could be done to prevent child deaths across all age groups.

" Although some contributing factors are relatively fixed, including a child's age, sex, and genetics, many environmental, social, and health service factors are amenable to interventions that could lessen risks and help prevent future deaths."

The study that exposed regional variations reviewed data on more than 4,000 infants and children aged 14 and under who died in England and Wales between 2009 and 2011.

For children aged one to four, the number of deaths per 100,000 of the population ranged from around 15 in the South East to 23 in the North West.

Among children aged five to 14, the rate varied between around eight per 100,000 in the East and South East to 10 in the North West and East Midlands.

Dr Sidebotham added: "It needs to be recognised that many child deaths could be prevented through a combination of changes in long-term political commitment, welfare services to tackle child poverty, and healthcare services.

"Politicians should recognise that child survival is as much linked to socioeconomic policies that reduce inequality as it is to a country's overall gross domestic product and systems of healthcare delivery."

Dr Hilary Cass, president of the Royal College of Paediatrics and Child Health, said: "We've known for some time that the UK performs badly compared to its western European counterparts when it comes to child mortality rates - but today's paper reveals the startling fact that one in five child deaths in England could be prevented. This is a serious wake-up call for both healthcare professionals and policymakers and we have to act urgently."