  Immigration is one of the most salient topics in public debate. Social media
heavily influences opinions on immigration, often sparking polarized debates
and offline tensions. Studying 220,870 immigration-related tweets in the UK, we
assessed the extent of polarization, key content creators and disseminators,
and the speed of content dissemination. We identify a high degree of online
polarization between pro and anti-immigration communities. We found that the
anti-migration community is small but denser and more active than the
pro-immigration community with the top 1% of users responsible for over 23% of
anti-immigration tweets and 21% of retweets. We also discovered that
anti-immigration content spreads also 1.66 times faster than pro-immigration
messages and bots have minimal impact on content dissemination. Our findings
suggest that identifying and tracking highly active users could curb
anti-immigration sentiment, potentially easing social polarization and shaping
broader societal attitudes toward migration.
