Combat 18 (1 = A(dolf) 8 = H(itler) ) was an organisation set up to combat Anti-Fascist Action. It achieved some notoriety in the media and was blamed for the 1995 Lansdowne football riot in Dublin.
Here are some videos:

This report was done shortly after the Lansdowne riot and features Manchester AFA.

True Lies documentary:

World in Action did no less than three reports on C18:

These videos are thanks to the fantastic work of 45antifascist