Irish Travellers suffer from a strange situation where the British classification and their own classifications differ.
Most tick the "White British" box on censuses, or "White Irish"
This is because most "Travellers" in my experience identify as Irish, in particular, with Northern Ireland, where they lived as a more "normal" lifestyle choice.
Irish Travellers behave this way because many are still in the mindset that the police will torture them if they capture them, which they did, many times. The state obviously has a bit of a bone to pick with Travellers, as Travellers are also, even using the most wide-spanning population metric of "Ethnic Traveller" separate from ethnic Irish, number at 300,000. Using this number, they are identical to Irish-British in almost all criminal prosecution cases, which itself is higher than English until adjusted for income level, where it becomes insignificant.
Except for terrorism-related, where they are probably the highest single ethnic group per capita in the world, given that they were so heavily involved with the IRA.
Using the lower boundary, those who identify publicly on the census as Irish Travellers, at 20,000, this group alone would have contributed hundreds of members to the IRA - even more using the wider 300,000 definition. The difference is in the census details - since Travellers occupy all three Native-UK census slots. Ethnic Irish Travellers are around 300,000 - proper nomadic Travellers only make up around 7% of the total population of "ethnic Travellers"
This is also a major part to why so many Travellers behave as they do - they never really chilled out like the rest of Ireland did. This is also to do with Ulster itself, where many are native to.
The separation in the definitions is somewhat new - historically, Irish Travellers were just considered as one of the Irish lifestyles - some live in villages, some live in cities, some live in caravans and tents. This was the same among all Gaelic groups, by the way, with many living semi-nomadically.
The history of the "ethnic group" if you believe Travellers are a distinct ethnicity is just sad - prior to around the Second World War, they actually had industries which they excelled in, namely horse breeding and showman entertainment - but over the last 80 years, the conditions just got worse and worse. Unlike foreigners, Travellers are distinctly native to the UK and only "separated" recently, with the worst living conditions in the UK throughout the 20th century. This is also why I can't stand blacks who bitch and moan about racism, especially trying to say that they had it bad in the 50s to the 70s. They had houses with running water and electricity in major cities, many had employment opportunities, and similarly Pakis owned small businesses - while at the same time, Travellers were in disgusting poverty, not even "ghetto" poverty, I'm talking absolute, stunted-growth, no-teeth, atleast-one-kid-will-die poverty.
In short, the opposite is true. Travellers lived, and some still live, in completely crippling poverty. Due to some (I suspect, hostile) intervention of bureaucracy and cowardly police officers who are afraid that they may end up in a ditch like so many were during the Troubles, the subset of the population most likely to commit crimes are separated from the rest of the population. I have no idea why that is, it'd be like finding the shittest trailer park you can, circling it and declaring the people in there to be of a different racial group.
TLDR Circling a subset of a far larger ethnic group doesn't suddenly make black crime acceptable. Doing the same to any ethnic group would have the same effect.
