The world's population will increase inexorably, swelling from 6.89 billion to 9.49 billion by 2050.

India is expected to overtake China with a population of 1.75 billion by 2050, according to the Population Reference Bureau, a United States body which supplies data to governments and institutions around the world.

India's population hit one billion just a decade ago and it now has a population of 1.19 billion.

According to The Telegraph, India will add the equivalent of the entire population of the European Union in a mere 40 years.

China's population is expected to increase modestly from 1.34 billion to 1.48 billion. China is currently the most populous country in the world.

The Population Reference Bureau also predicted that Britain would be the biggest country in Europe by 2050, overtaking both France and Germany, as its population will swell by 15 million from today's 62.2 million to 77 million.

The predicted population of Britain would be higher than that of France, projected to be 70 million and Germany, which is predicted to have 71.5 million citizens by 2050.

The population of France will increase at half the rate, adding 7 million to its 63 million. Germany's population is expected to fall sharply from 81.6 million to 71.5 million because of a lack of immigration and a far lower birth rate than that in Britain.

Europe, in total, will see its population dip from 739 million to 720 million, because of its low birth rate.