Fewer residents in Boston identify as English than a decade ago as more opt for a British identity, new census figures show.
Jon Wroth-Smith, census deputy director, said the recent data highlights that we are living in an "increasingly multi-cultural society" across England and Wales, with fewer people saying they belong to a particular nation.
The figures from the Office for National Statistics show 19% of people in Boston identified as English only when the census took place last year, down significantly from 66% in 2011.
And 41% selected British only in the recent survey while 10% chose the identity a decade ago.
Overall, about 79% of people in Boston chose any UK identity in 2021, down from 86% in 2011.
Across England and Wales, 90% usual residents identified with at least one UK national identity – a slight decrease from 92% in 2011.
The proportion of people identifying as English only saw the sharpest fall, from 58% selecting the national identity 10 years ago to just 15% last year.
People opting for Welsh only also fell slightly, from 3.7% of the population 10 years ago to 3.2% last year.
Nationally, 55% said they identified as British – leaping from 19% in the previous census.
The census also revealed shifts in ethnicities across England and Wales with the proportion of people identifying as white falling to 82% last year from 86% in 2011.
And 74% of the total population in identified their ethnic group as white English, Welsh, Scottish, Northern Irish or British in the recent survey – down from 81% a decade prior.
About 95% of people identified as white in Boston in 2021, down slightly from 97% in the previous census.
Additionally, 75% identified as white English, Welsh, Scottish, Northern Irish or British – a slight decrease from 84% in the previous census.
Mr Wroth-Smith said: "The percentage of people identifying their ethnic group as 'White: English, Welsh, Scottish, Northern Irish or British', continues to decrease.
"Whilst this remains the most common response to the ethnic group question, the number of people identifying with another ethnic group continues to increase."
In Boston 1,443 residents (2%) identified as Asian or Asian British and 467 (1%) selected black or black British as their ethnicity. A further 1,015 (1%) said they were mixed ethnicity.