Artist Brian John Spencer by NY photography / David Paul Larson

Brian John Spencer created the image in response to a video by Sinn Féin MP Barry McElduff.

The MP posted a video of himself with a Kingsmills loaf on his head on the anniversary of the killings. The IRA killed ten Protestant workmen at Kingsmills in south Armagh on 5 January 1976.

Mr Spencer told the BBC his thoughts were “with the Kingsmills families”.

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“The job of an artist is to look at what’s happening and point out the hypocrisy and the bluffery,” he told BBC News NI.

“The material with the van and the blood could be seen as obscene, but the past was gory and brutal and tough images have to be seen to reject the past and move forward together.”

Mr Spencer said he created the cartoon to illustrate “lecturing fatigue” within the unionist community, brought on by Sinn Féin’s stance on equality issues.

“It’s interesting for me to watch Sinn Féin going around lecturing, but I worry because they have these young people from the next generation backing the old line,” he told the BBC.

“There’s not much talk of rejecting the past.”

The Kingsmills cartoon was re-posted on Twitter by DUP MLA Christopher Stalford on Wednesday, but he later deleted it at the request of a victim’s relative.

Alliance Party leader Naomi Long also called for politicians to remove the image from their accounts.

She said: “Artists, of course, have a right to freedom of expression, and will often use images which are provocative or even grotesque in order to make their point.

“However, we are not artists, comedians, or satirists, we are supposed to be politicians.”

Colin Worton, whose brother Kenneth was killed at Kingsmills, told the News Letter he supported the cartoon.