The 2011 census will aim to map migrant populations in England and Wales, proposals published today reveal.
The planned census, to take place on 27 March 2011, will ask migrants their date of arrival into the UK and their intended length of stay.
A new question on citizenship also requires respondents to disclose which passports they hold.
National statistician Karen Dunnell said: "It was identified as the easiest way to get people to answer a question about their national citizenship, which is a very difficult concept."
She added that it was vital migration estimates were improved, and admitted: "You cannot guard against getting a shock when you get to the census."
Glen Watson, 2011 census director, said: "The information we have on migration at the moment is insufficient, and is not meeting the needs of our users.
"The information is incredibly valuable so we are doing our best to get it."
The Government White Paper on the 2011 census said the questions on migration are "particularly important", and states: "Migration accounts for much of the growth or decline of the population of areas between censuses.
"The information collected in the census will allow inferences to be made about the level and pattern of migration in other years."
For the first time, the census will allow people to record their national identity as being particular to a part of the UK.
The question on how the respondent describes their national identity gives six possible answers: English, Welsh, Scottish, Northern Irish, British or other.
The move follows criticism of the 2001 census for failing to provide people with a tick box to state their national identity.
Peter Benton, deputy director of the 2011 census, said: "There has been a very strong demand for people to be able to state their own identity, especially to say they were Welsh. We looked for the best way for people to express this."
New categories have also been added to the ethnic origin section of the proposed survey, which will now give people the opportunity to describe themselves as being of Arab, Gypsy or Irish traveller background.
The marital status section has been extended to include same-sex civil partnerships, to reflect the change of law since the 2001 census.
A question on sexual identity was considered by the UK Statistics Authority but rejected.
Mr Watson said: "The census is a compulsory exercise and the householder quite often fills in the form on behalf of the whole household.
"That is then a difficult environment to accurately collect information on people's sexuality, which is clearly a private matter."
A test survey carried out on the question of sexual identity did not return useful information, Mr Benton added. One in seven of those questioned did not answer, or said they did not wish to state their sexual identity.
The census, costing an estimated £480 million, will be the first that can be completed online. A quarter of all responses are expected to be gathered that way.
A total of 35 million questionnaires will be distributed by hand and by post.
Census staff will visit households that do not return the questionnaire, which is a legal obligation.
Mr Watson said: "We have made some changes to the design of the census for 2011, learning from experience in 2001 and using technology to assist with our massive field operation, for example giving people the opportunity to fill the questionnaire in online.
"What we have not changed, however, is our 200-year-long commitment to the security and confidentiality of personal census data."
He said data protection was a "top priority", and added: "We are hoping to get the message across to people that this is a very secure operation, and that their data will be safe and secure with us.
"One of the things we will have to get across is that we do not share information with other government departments.
"There is no link to the ID card scheme, or any other such scheme.
"One thing of concern would be if there is a data loss in another department in the run up to the campaign. We would have to make it clear it does not in any way undermine or threaten our operation."
A publicity campaign will be launched to increase awareness of the census, he said, with up to three million calls expected at the census public contact centre.
Other new questions include those asking people the number of bedrooms in a household, the type of central heating and if they have a second home.
Residents in a household will also be able to register their relationship to each other as step-brother or step-sister for the first time.
One element unchanged from the last census is the religion question, providing a blank box which led some to state their religion as Jedi in 2001.
Mr Benton said that option was still open, but added: "People need to give as good and accurate an answer as they possibly can."
The proposed 2011 census has 39 questions for individuals, three more than last time. It is expected to take 10 minutes to complete per person.
A total of 94 per cent of the population completed the last census, with 38 people prosecuted for non-compliance.
Mr Benton said it would be impossible to gain an exact population figure, but added: "Our aim is to be within 0.2 per cent of the actual true population."
The planned survey will be tested with a census rehearsal targeting 135,000 homes in October 2009.
The areas chosen are Lancaster, the Isle of Anglesey and the London borough of Newham.
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