Singapore has been named the world’s healthiest country, according to a list which ranks countries using data from the United Nations, the World Bank and the World Health Organisation.

The Bloomberg rankings gave each country with a population of 1 million or more a health score and a health-risk score.

Each country’s place was calculated by subtracting their risk score from their health score.

The health score is based on factors such as life expectancy from birth and causes of death, while health-risk is based on factors which could impede health such as the proportion of young people who smoke, the number of people with raised cholesterol and the number of immunisations.

Singapore came top with an overall score of 89.45 per cent, Italy ranked second healthiest with 89.07 per cent, and Australia came third with 88.33 per cent.

Israel, in sixth place is the only Middle Eastern country placed in the top 10, while North and South American countries were not present in the top 20.

The UK also failed to reach the top 20, ranking at number 21 with a score of 76.84 per cent, behind Belgium, Ireland and Norway.

At the other end of the scale, the African country of Swaziland was named the least healthiest country in the world, scoring an overall grade of just 0.26 per cent.

African nations dominated the bottom of the list with Lesotho, Democratic Republic of Congo, Chad and Mozambique falling in the bottom 10.

"The data is a useful guide for policy makers, who might look at the practices of higher-scoring countries to improve their own countries’ health scores", according to the World Economic Forum.

The word “healthy”, however, is open to interpretation, the WEF stress, saying a ranking defining “healthy” by "quality of life" rather than "life expectancy" might include lower-income countries which report higher levels of life satisfaction.

Despite scoring poorly in Bloomberg’s list, earlier this year Chad was revealed to have a world’s healthiest diet, according to new research comparing global eating habits.

The study also revealed a global rise in the consumption of healthy food, such as fruit and vegetables, but this was overtaken by a concerning increase in the amount of junk food being eaten.

UN data has also been used to map the distribution of over 600 of the largest urban areas in the world.

The largest urban areas in the world Esri UK (Esri UK)

The size of each point represents the current estimated population, while the darker the colour of the point - the greater the population growth since 1950.

The healthiest countries in the world:

1. Singapore

2. Italy

3. Australia

4. Switzerland

5. Japan

6. Israel

7. Spain

8. Netherlands

9. Sweden

10. Germany