The black-led human rights organisation, The 1990 Trust were first to call for Wade's resignation after she published the cartoon drawn by Bill Caldwell.

"This is a deeply racist and offensive cartoon which will be extremely offensive to Black communities, and people of all races", Karen Chouhan, chief executive of The 1990 Trust said.

"I am calling on Rebekah Wade to resign. The cartoon is completely unacceptable. It is made worse by a headline branding the President of Equatorial Guinea a cannibal".

Alex Pascall, chair of the National Union of Journalists Black Members Group, called the cartoon "atrocious", adding: "The Sun has no right to paint Black people like that. It is an insult to every Black person."

Author Mike Phillips added: "It's a stupid insult. Even the prejudices and their expressions have moved on from that. The racists nowadays are more subtle and clever than that.

"They're clearly saying 'Mark Thatcher, a white man, being arrested by Black people is not only injust but the result of savagery of Black people. I suspect this isn't going to play as well as they think."

Writer and broadcaster Marc Wadsworth said Wade should step down. "It's bare-faced disgusting racism - the Sun of old. It's the sort of thing you wouldn't expect from Rebekah Wade.

"The Sun is supporting Mark Thatcher's version of events. She's clearly not doing her job. She should be sacked over it. She does not deserve to keep her job".

As Blink ( http://www.blink.org.uk/) published this story The Sun were not able to offer any comment. Neither Wade, Caldwell or any other person from the Sun was available for comment.

Blink is urging readers to complain to the Press Complaints Commission. They can be emailed on:  complaints@ppc.org.uk

Today's Sun features a page-lead story headlined "Mark's at the Mercy of Cannibal", which suggested that the President of Equatorial Guinea ate his opponents' testicles.

The story follows the arrest in Cape Town, South Africa, yesterday of Sir Mark Thatcher, son of the former Prime Minister, over claims he aided an attempted coup against Equatorial Guinea's President Teodoro Obiang Nguema. The West African state has recently discovered large oil reserves.

Thatcher, 51, was ordered to pay £165,000 bail and remains under house arrest pending a hearing in November. 13 other people are on trial in Guinea's capital over charges relating to the same attempted coup.

70 other alleged mercenaries were arrested and are awaiting trial in Zimbabwe over claims they attempted to buy arms to transport to Guinea. They include an old Etonian former British SAS captain Simon Mann, who is believed to be a friend of Thatcher's and lives on the same Cape Town street as him.

Last October Sun editor Wade was forced to do a u-turn after the front page headline 'Bonkers Bruno' - referring to former boxer Frank Bruno's mental health sectioning - upset readers.

While editor of the News of the World, Wade's anti-paedophile campaign in the wake of the killing of Sarah Payne was blamed for a creating a climate that led to a vigilante attack on a paediatrician.

Media expert Paul Macey, of the Creative Collective, called for a boycott of The Sun. He added: "The Sun has run overtly racist articles over a long period. On the day that Michael Howard attacks political correctness we have something that shows that PC hasn't gone far enough".

LATE NEWS: Fergus Shanahan, deputy editor of The Sun, told Blink that his paper had not received any complaints about the cartoon. He said: "I’d be extremely disappointed [at accusations of racism] because the Sun is not a racist newspaper – never has been.

"We bend over backwards to ever avoid accusations of racism. I can't remember the last time anyone ever suggested anything in the Sun was racist.

"The fact that some people involved in the story are black Africans is as far as we're concerned not an issue. You are the first person, the only person, to contact us today… about this story.

"That's why with the best will in the world we're puzzled because if we'd had thousands of telephone calls we'd have thought to ourselves 'well, hold on a moment...'."

"We have ten million readers and if we'd printed something that people genuinely felt a sense of outrage over believe me sir, we would have thousands of calls by now".

Complaints can be directed to the Sun editor on:  rebekah.wade@the-sun.co.uk