Hundreds of obese four-year-olds are among more than 6,400 children treated at specialist NHS weight loss clinics, new figures reveal.

The official data - published by NHS England for the first time today - lays bare the alarming scale of the nation's childhood obesity crisis.

Those receiving care are all 'extremely' overweight for their age, with the four-year-olds weighing an average of 33kg (5st 3lbs), which is more typical of a 10-year-old.

Almost a fifth were suffering from high blood pressure, while others had type-2 diabetes or early signs of heart disease, usually developed in older age as a result unhealthy lifestyles.

Clinics have even turned to weight loss jab to help hundreds of these kids slim down, regularly starting from 11-years-old.

England's top paediatric doctor last night described childhood obesity as 'one of the biggest public health challenges facing the country' and warned lives are being cut tragically short as a result.

There are 39 specialist Complications from Excess Weight (CEW) clinics for children in England, with the first opening in 2021.

These have treated 6,497 children aged from four to 17 over this period, delivering bespoke packages of care, including diet plans, mental health support and lifestyle coaching.

The youngest patients treated by the clinics were just four years old, with 423 so fat they needed help at this age.

Some 1,088 were aged five to eight, 1,791 aged 9 to 12 and 3,137 aged 13 to 17. The age of a further 58 is unknown.

NHS England said the children treated at the clinics have 'benefited from help to lose weight and live healthier lives'.

This is supported by new research being presented at the European Congress on Obesity, in Istanbul, this week, which shows kids treated at a CEW were an average of 10kg lighter two years later than comparable youngsters only seen by their GP or community health teams.

The clinics are staffed by specialist doctors, nurses, psychologists, social workers and dietitians who adopt an 'holistic approach' to treating patients.

Previous research by life sciences consultancy Stradoo found a child who is living with severe obesity at age four and does not lose weight has a life expectancy of just 39.

Losing this weight can give back decades of life.

Around one in four children in England start primary school overweight or obese, rising to more than one in three by the time they leave aged ten or 11.

People who are obese as children are more likely to be obese as adults, leaving them at increased risk of heart disease, cancer and musculoskeletal conditions.

Patients can be referred to a CEW clinic by a community or hospital paediatrician, a GP or childhood mental health services.

They must have a body mass index above the 99.6 percentile - meaning they would be one of the four fattest among a group of 1,000 children their age - and have an illness linked to their excess weight.

New analysis of a subset of children treated by a CEW, also presented at the conference, reveals 17 per cent had high blood pressure, 6 per cent had type-2 diabetes and 17.5 per cent had abnormal levels of fat in their blood, which can be a sign of early heart disease.

Some 29.3 per cent had metabolic dysfunction-associated steatotic liver disease, 17 per cent had obstructive sleep apnoea and 8.7 per cent had deliberately self-harmed.

A further 8.7 per cent had anxiety, 28.6 per cent autism, 12.4 per cent attention deficit disorder and 23.6 per cent had a learning disability.

Professor Simon Kenny, national clinical director for children and young people at NHS England, said: 'Severe obesity can impact all aspects of a child's life - affecting their physical health, mental wellbeing and confidence - so it is fantastic that NHS CEW clinics are helping thousands of children and young people turn their lives around.

'These specialist clinics support children to lose weight safely and build healthier long-term habits through tailored care from expert NHS teams.

'In some cases, these clinics are helping children who could otherwise face a life cut tragically short —dying decades too soon — to look ahead to a full and healthy life.

'Childhood obesity remains one of the biggest public health challenges facing the country, and the NHS is committed to stepping in early to help prevent serious long-term health complications.'

Dr Cath Homer, who worked on the study and is an associate professor in obesity and public health at Sheffield Hallam University, said: 'The increasing prevalence of severe obesity and its complications amongst children and young people, is fuelling rising demand for specialist support and treatment that goes beyond traditional community-based weight management services, and our research suggests that CEW services are an effective way to support patients for better health and weight management.'

Katherine Jenner, from the Obesity Health Alliance, said the figures should be a 'wake-up call' and Dr Helen Stewart, from the Royal College of Paediatrics and Child Health, described the number of children being treated at CEWs as 'extremely concerning'.