The Office for National Statistics estimates the U.K. population was 61.14 million last June, with 6.97 million born outside the country.
Both the number of immigrants and their proportion of the population have nearly doubled since 1991, The Daily Telegraph reports. Most of them, 4.7 million, come from outside Europe.
A quarter of babies now are born to foreign mothers, the figures show.
Prime Minister David Cameron said Wednesday that immigration, which soared under the previous Labor government, had brought "discomfort and disjointedness" to some neighborhoods. He said the level should be cut from more than 200,000 yearly to the "tens of thousands" before the next election.
Business Secretary Vince Cable, from Cameron's Liberal Democrat coalition partner, chided his remarks as "very unwise" and risking aggravating racial tensions.
MP Nicholas Soames, Conservative co-chairman of the Cross-Party Group on Balanced Migration, said Labor's "spineless and futile" immigration policies had led to a "grave situation."
"Immigration under the last government became completely out of control," he said.