Boston, Spalding and Wisbech have seen some of the highest levels of immigration in the UK in recent years but are the least integrated a new report has found.
Boston, which has seen an influx of mostly Eastern European workers over recent years, was deemed the least integrated, based on figures including whether individuals held a UK passport, how many households were ethnically mixed and employment statuses.
It was closely followed by neighbouring Spalding and Wisbech.
The think-tank which published the research said that local councils should be given a statutory responsibility to improve community integration.
Policy Exchange said forcing councils to publish regular audits would focus minds on action to ensure a better ethnic mix, for example of pupils in particular schools or staff in public services.
And the Government should compile a comprehensive national analysis of the picture every three to five years, it said as it launched a new Demography, Immigration and Integration Unit.
The unit’s head David Goodhart said: “If there’s a national consensus that we want to avoid parallel lives, any pressure on them to produce figures and to get councillors thinking about how they can make schools and neighbourhoods more mixed is a help.
“Ethnic minority integration has shot up the political agenda in recent months and it is useful to know where the biggest challenges and the often quiet success stories actually are.
“As our index shows the integration picture is a mixed one but in some places people, of all backgrounds, fear that society is changing too fast and that too many people are living parallel lives.”
Analysis using data from the 2011 consensus - related to 160 places with a population over 20,000 of whom at least 15% were from an ethnic minority - showed there were significant variations in the extent of inclusion, he said.
The 10 least-integrated places were identified as Boston, Wisbech, Oldham, Spalding, Bradford, Batley, Halifax, Blackburn, Keighley and Accrington.
The most integrated were mostly prosperous suburbs or small towns around London and Birmingham, with the largest minorities being successful Indians or Europeans.
Top was Amersham, followed by Sutton Coldfield, Loughton, Potters Bar, Letchworth Garden City, Stretford, Bushey, West Bridgford, Rickmansworth and Esher.
Mr Goodhart said: “We know that people of similar backgrounds tend to cluster together but we also know that a good society needs a sense of trust and mutual regard that crosses social and ethnic boundaries.
“It is critical that this country retains its traditions of openness and individual rights and some sense of mutual regard between citizens. That is why the government should try to promote mixed communities.”