The coalition published an excerpt of "Royal Babylon: The Criminal Record of the British Monarchy" by poet Heathcote Williams.
In it, Williams claims the Royal Family "lubricates Britain’s wars" and accuses the Queen of heading a "military-monarchy complex" – a "cynical industry" which enriches the Windsors.
Jeremy Corbyn has resigned as chairman of the Stop The War Coalition
The Sunday Telegraph claims senior Labour figures criticised the sentiments expressed in the poem, which led to Corbyn resigning some five hours later.
The Telegraph quotes Kevan Jones, the shadow defence minister, as saying: "This slur on the Queen will be highly offensive to members of our Armed Forces and many ordinary Labour voters.
"I am sure these are not the views of Jeremy Corbyn but it is time he distanced himself from some of the more extreme elements of the anti-war coalition," he said.
Corbyn's spokesman said his decision to quit as chairman was entirely unrelated to the poem.
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He told Sky News: "It was always agreed that if Jeremy was selected (as Labour leader) he would step down in a number of roles, one of which was chairman of the Stop The War Coalition.
"This is due to the number of engagements and commitments that come with being the leader of the Opposition."
The Stop The War Coalition's website has published a personal explanation from Corbyn on his decision to leave the role in which he also praises the group.
The leader says his new job requires his "undivided attention", but also said the coalition "represents the very best in British political campaigning, and its cause of opposing war, upholding civil liberties and resisting Islamophobia will remain my cause".