Four fifths of English people think the country is crowded, a survey has shown.
The poll comes after the latest official projections showed the UK's population is on course to reach 70 million within 16 years.
About one in 30 (3%) felt England was not crowded, with about one in six saying it was "about right", the survey showed.
More than three quarters of Britons were concerned about the population projections, with more than a third "very concerned", and only a fifth not worried by the prospect, according to the poll.
Campaign group Migration Watch UK, which asked YouGov to carry out the survey of more than 1,500 Britons, including more than 1,300 English people, said it showed the level of unease about the rising population.
It has launched a petition urging the Government to take "all necessary steps" to curb immigration and stop the UK's population from swelling to more than 70 million. More than 88,000 people have signed up to the e-petition on the Government's website so far.
The rise from 62.3 million last year to 70 million is the equivalent of building seven cities the size of Birmingham, the campaigners said.
Home Secretary Theresa May has said the pace of change seen in the rising population is "one of the reasons why we need to take action to control immigration".
The survey showed that more than two-thirds of Britons backed moves to reduce net immigration to 40,000 a year in a bid to keep the population under 70 million, with about one in eight against such a plan.
Sir Andrew Green, the campaign group's chairman, said: "This poll explains the huge public support for our e-petition and demonstrates quite clearly that most people think England is already overcrowded. By more than 25 to one, English people consider England to be already crowded."