Britain's population 'could reach 109 million by 2081'

Britain's population could almost double to 109 million during the lifetime of today's children, according to new official projections.

The forecast reignited the debated over immigration levels, with the Government facing accusations of presiding over an unsustainable increase in the numbers of migrants.

The Office for National Statistics predicted today's population of 60.6 million could increase to 75.4 million by 2031, 91 million by mid-century and pass 100 million by the late 2060s if levels of immigration, fertility and life expectancy all remain high. It could reach 108.7 million by 2081, the furthest ahead the ONS looked.

Such rapid growth – equivalent to 640,000 a year – would strain housing, schools, hospitals and the transport network. The numbers of people aged 75 and over would rise from 4.7 million today to 19.4 million in 2081, with implications for the cost of pensions and health care. The total of under-14s would go from 10.7 million to 17 million in 2081, forcing authorities across the country to build hundreds more schools. And the overall population growth would outstrip the current government drive to build another three million homes by 2020.

Liam Byrne, the Immigration minister, said: "These projections show what might happen in 75 years' time unless we take action now. Frankly, it underlines the need for the swift and sweeping changes we are bringing to the immigration system in the next 12 months, which will include the introduction of an Australian-style points-based system, so only those Britain needs can come to work and study."