Childhood obesity in the UK has reached ‘alarming’ levels with up to a third being dangerously fat, warn doctors.

They claim Britain is ‘the fat man of Europe’ and the problems have set in by the age of nine.

A report also says the UK’s child death rate is the second worst in western Europe, with an estimated five extra deaths a day compared with the best performing country.

Scroll down for video

British girls under 20 are the fattest in Europe – topping a league table of 22 nations in Western Europe

One in 10 children – around three in every classroom – has a diagnosable mental health condition but even those identified are often not treated properly.

In a wide-ranging report, the Royal College of Paediatrics and Child Health (RCPCH), which represents doctors specialising in children and young people, issues a wake-up call to politicians.

It says childhood obesity statistics ‘continue to cause alarm’ with 26 per cent of boys and 29 per cent of girls overweight and obese ‘storing up serious health problems for the future’.

British girls under 20 are the fattest in Europe – topping a league table of 22 nations in Western Europe.

British boys under 20 are 10th in the league table, with Greece at the top where one-third of boys are ranked as fat.

British boys are 10th in the league table, with Greece at the top of the list as one-third are ranked as fat

Recent research for the period 1980-2013 says there has been a substantial increase in overweight and obese children and adolescents in developed countries, including the UK.

The RCPCH wants a ban on advertising of foods high in saturated fats, sugar and salt before 9pm, and restrictions that stop them being advertised on internet ‘on-demand’ services.

Food and nutrition training should be mandatory for teachers as part of a bid to improve children’s diet in schools, along with more activity for children promoted via more cycle lanes and 20mph speed limits.

The Vision2015 report says death rates of children under five are second to bottom in a league table of 21 nations, at 4.9 deaths per 1,000 children born compared with 7.0 in Malta.

The RCPCH wants a ban on advertising of foods high in saturated fats, sugar and salt before 9pm, and restrictions that stop them being advertised on internet ‘on-demand’ services

The number of needless deaths among preschool children is similar up to the age of 14, with five extra dying each year who would not die in Sweden, among the best performing countries.

The number of children dying needlessly each year in the UK compared with Sweden amounts to almost 2,000 each year.

RCPCH President Dr Hilary Cass said there would be ‘serious consequences’ if no concerted effort is made by the next Government to improve children and young people’s health.

She said politicians must give a similar priority to young people that had been awarded to the elderly.

She said ‘The main focus of health and social care policy from successive Government has been on meeting the needs of an ageing population.

‘Many of the big ticket policies – such as pension increases, winter fuel allowances and free TV licences - have made a welcome difference to many older people We now want to see equal focus given to our younger population.

‘Not only should this be done because it directly benefits children and young people but also because it will improve the health of the nation as a whole.

‘Healthy children are more likely to be healthy adults – and of course the reverse is also true.’

Lisa Murphy, a member of the RCPCH’s Youth Advisory Panel, said the health of young people in the UK has been falling behind the rest of Europe’ for too long’.