An undercover investigation by BBC Wales into a group campaigning against Muslim extremists has found links with neo-Nazi supporters.
Secretly-filmed footage in Monday's Week In Week Out programme also exposes criminal activity among some Welsh Defence League (WDL) supporters.
Publicly, the WDL says it is a non-racist organisation.
A judge who has examined the evidence in the programme said some were acting to "inflame racial hatred".
The WDL - aligned to the English Defence League - was set up last year by an ex-soccer hooligan and author Jeff Marsh in response to Muslim extremists abusing troops returning from Afghanistan.
It has attracted hundreds of followers and held demonstrations in Cardiff, Swansea and Wrexham.
Posing as a new member of the group, an undercover journalist accompanied a number of Welsh supporters to a protest.
Some were caught on camera and online, making racist comments about Muslims.
Two admitted involvement in racist violence at demonstrations organised by the defence leagues in other parts of the country.
One invited other WDL followers to join him in burning a Koran and joked online about how best to kill black people.
Another talks about driving Muslims out of the south Wales valleys.