Speaking English is the most important British characteristic, a survey finds.
British citizenship was the main characteristic for 83% of people
Language was the main criterion for 87% of the 3,000 people asked, just ahead of citizenship on 83% and respecting institutions and laws on 82%.
The survey's authors think it shows more people believe being British can be learnt, not just born into.
But the 21st British Social Attitudes survey also shows attitudes towards immigration have hardened, with more people linking it to crime.
The survey by the National Centre for Social Research (NatCen) found that 74% of people last year thought immigration should be reduced, up from 65% in 1995.
In the same period, the percentage of people wanting Britain to take stronger measures against illegal immigrants rose from 78% to 82%.
Even those groups which were previously pro-immigration, such as graduates and Labour supporters, have seen attitudes harden.
One of the survey's authors, Alison Park, told the BBC's Today programme: "People seem much more willing now to link rising immigration with rising crime.
"They are also more likely to feel that immigration actually closes Britain off to new ideas and cultures."
She said there were two types of British characteristics, those people are born with and those that can be "acquired".
About 60% of people emphasised a mixture of both, but a growing number - about a third - emphasised only those things you can acquire.
Ms Parks said this group was made up of largely young people.
She added: "Everything being equal, it is likely that group will increase over time as the older generation, particularly some of the pre-war generation, who have closed views about these things, die out."