In most of the English-speaking world, which happens to be white, anti-Irish racism has decreased dramatically, including in the United Kingdom. The primary focus of 21st century racists is identifying and tormenting people with skin color darker than theirs. The lingering stereotypes about the Irish may still be with us, but they are not taken very seriously.
Racism in general has been decreasing since the 19th century, so the anti Irish racism since that time has been doing so as well. Its far easier today to understand the cultural and ancestral differences that have led to disagreements in the past, and, while people aren't perfect, there has been much progress.
There is never really a way to eradicate racism throughout a population, but it has severely decreased in severity from the 19th century. Irish people once had a very, very difficult time finding employment and just living day to day. Nowadays there is still some people who are racist, but it's not as many.
Anti-Irish racism has decreased in the United Kingdom since the 19th century. A lot of things have changed since the 19th century and racism is one of those things. It used to be normal to be racist against anyone that was of different race than yourself. Time has bought us closer together and the hatred is gone.
I believe the anti-Irish racism has decreased in the United Kingdom since the 19th century. Many things have changed since the 1800's and during that time it was considered normal to be racists against anyone who wasn't the same nationality as yourself. New York City was a mess. Since then attitudes have shifted, especially with globalization, therefore the tensions have decreased in the United Kingdom as well.