Scottish? Or British? For generations many Scots were happy to be a bit of both. Now, for the first time, they will officially have to decide between the two.

The Scottish Government yesterday published the likely questions on national identity for the next census. People living in Scotland in 2011 will be asked to tick one of 21 boxes that they think best defines their ethnic or national background. There will be a box for "Scottish" and a box for "British" but none for both.

Government statisticians want to get to the bottom of who the residents of Scotland think they are. Polls have persistently shown most people living in Scotland feel more Scottish than British. But what will they say when they have to make up their mind between two identities that are exclusive rather than complementary?

"I'll put British," said Bill Aitken, a veteran Tory and Unionist who it would be hard to mistake for anybody but a native Glaswegian. "I am a British Scot. This is clearly the Scottish Government trying to drive a wedge between Scotland and the rest of the UK. While we are all proud of our Scottishness, we are British as well. This is just a juvenile attempt to create divisions where they don't exist."

London-born and English-accented Nigel Don, a fellow MSP, has a different take. "I would put myself down as Scottish," the Nationalist said. "I have never had any doubts about that, regardless of where I was born. And that would not be a political answer."

The Scottish Parliament will have to give its blessing to the census forms before they are used. But the proposed new questions on national origins will be used by the Scottish Government for a whole range of purposes, including its efforts to monitor the ethnic background of people who apply for public-sector posts. The reason: to ensure nobody is discriminated against on racial grounds.

"A national identity question is also being tested and developed for the census and relevant Scottish Official Statistics," a spokeswoman for the Scottish Government explained. "This will let people express their national identity fully - be that Scottish', British' or any other national identity - before expressing their ethnicity. The Registrar General is developing a question for publication in autumn 2008."

The last census, in 2001, also quizzed people about their ethnic origins, but only offered 14 options. The first, for people who categorise themselves as White, was "Scottish", the second "other British", allowing Scots who felt British to put "Scottish" without denying their Britishness. Whites could also choose to be Irish or Other White.

Now there are far more options. First is "Scottish". Then come "English", "Welsh", "Northern Irish", "British", "Irish", "Gypsy/Traveller", "Polish" and "Any Other White Ethnic Group".

The form will also include another 12 boxes, for people of Asian, African and Caribbean or other descent, including, for the first time, a subcategory for people who identify themselves as Arabs.

Rob Wishart, Scotland's Chief Statistician, said: "Since the last census in 2001, Scotland has become a more ethnically-diverse country. So it is vital that the next census (in 2011), and other Scottish Official Statistics, provide good information about different ethnic groups in Scotland.

"That will help ensure that public services are geared to everyone's needs and that any discrimination is detected.

"To do that effectively, we need to ask the right question in the census and other Scottish Official Statistics. We have consulted a lot of people and held useful discussions, as well as testing a wide range of possible questions. We believe that we have chosen a question which people can understand and answer easily, but which also allows people to record their ethnicity in the way which best suits them and provides the information which is needed to tackle discrimination and inequality."

The decision to review ethnic classifications in statistics was first ordered by the then Labour-LibDem administration in 2002. The Equality and Human Rights Commission has, so far, endorsed the decision. The Office of National Statistics will decide how it will count people's ethnic and national identity later.

Some Labour politicians were yesterday bristling about the wording of the questions, however. Frank McAveety, a Labour MSP and one of hundreds of thousands of Scots of Irish ancestry, warned the end results of any such census question wouldn't say very much about Scotland's appetite for independence.

He said: "Statistics could misrepresent who people think they are. I am Scottish and I am British but if I had to state a preference, I would say I am Scottish." What will we find out? Just how strong Scottish identity is. For the first time we will know how many Scottish residents, regardless of their views on the constitution, regard themselves as first and foremost Scots. How many English people live in Scotland. Previous censuses and surveys have asked how many people see themselves as not Scottish but British and how many people were born in England. The new model will pinpoint the exact number of people who regard themselves as being English, by far the biggest minority national group north of the border. How many Poles have come to Scotland. There is remarkably little robust information on the exact number of people to come to Scotland from Poland - and other parts of Eastern Europe - since they were given the right to live and work here in 2004. The new questions won't, however, measure how many Scottish residents of Asian, African or other ethnic backgrounds regard themselves as, say, "Scottish Asian" rather than "British Asian". Bluntly, people who regard themselves as white have to decide whether they are Scottish or British. People who define themselves as Asian, African or of other minority groups can't do so, even if they wanted to.