The UK population topped 60m last year
Tony Blair has told MPs the UK has no policy on controlling the size of its population.
Appearing before the Commons liaison committee he said there was a migration policy but no population policy.
And he argued it was impossible to give clear facts, rather than opinions, about the benefits or disadvantages of migration to Britain.
Labour MP Tony Wright said a debate was needed or the danger from right-wing extremists would get worse.
During his appearance, Mr Blair was also grilled about services such as schools and hospitals coming under strain in some areas because of an influx of East European migrants.
Mr Wright said the UK's population had topped 60 million for the first time last year and was expected to rise 12% in the next generation.
The rises were equivalent to having a new Oxford, a new Middlesbrough and a new Ipswich every year, he said.
And migration was the main driver, he told the prime minister.
