Annual immigration must be slashed by three-quarters if the UK population is not to reach 70 million by 2030, a senior MP warned today.
Tory former minister Nicholas Soames said failing to bring immigration under control "very substantially" could even lead to the total rising to 85 million.
The MP for Mid Sussex, who co-chairs the Cross-Party Group on Balanced Migration, said ministers remained "in denial" over the impacts of increasing population growth.
He highlighted the impact on schools, maternity units and social housing and said England was now the most overcrowded country in Europe alongside Holland.
Mr Soames was speaking in a debate in Parliament's Westminster Hall in which his warnings were echoed by Tory and Labour MPs.
The subject is increasingly being raised by the mainstream parties ahead of the general election. There are fears that a failure to address the issue will play into the hands of the extreme-right British National Party.
Prime Minister Gordon Brown has acknowledged the public's fears, pledging to tighten rules on migrant workers, while Tory leader David Cameron has indicated that a Conservative government would seek to limit net immigration to the "tens of thousands" a year.
Office for National Statistics projections suggest that, if current trends continue, the UK's population will grow from 61.4 million in 2008 to more than 70 million by around 2030, with net migration accounting for about five million of the increase.
Today Mr Soames told MPs: "The only way to limit our population is to get immigration down very substantially. Indeed it must be reduced from last year's 160,000 to 40,000 or less if we are to avoid a population of 70 million.
"Failure to bring immigration under control means a continually growing population, well beyond 70 million, even to 80 or 85 million in the latter part of the century."Reuse content