The large group of passengers were seen clapping as they sang 'Ooh ah, up the Ra' in footage taken on Saturday. The song, taken from the Celtic Symphony by the Wolfe Tones, is associated with support of the Irish Republican Army who carried out a series of bombings and assassinations in their long campaign of terror. But politicians have today slammed the footage as 'profoundly disrespectful' amid fears the chant is becoming 'normalised'. Alliance Party MP Stephen Farry said on Twitter: 'More disgraceful behaviour. We are seeing a growing pattern of incidents in sectarian chants across different parts of society.'