In 2008 I spoke to Anita Singh, former campaign organiser of Peta, about another of its campaigns that had upset a number of women. To mark Mothering Sunday, it staged an event to raise awareness about factory farming and the particularly unpleasant technique in which sows are squeezed into narrow metal stalls barely larger than their own bodies. A pregnant member of Peta's staff knelt on all fours in a metal cage in full view of the central London public.

"Peta's aim is to alleviate animal suffering," Singh told me. "It is certain that we never set out to insult or alienate any groups, in fact the opposite, we are trying to reach out to the masses. Using activists who put themselves on the line, who have done the ads, or using a woman's body to show that animals are made of flesh and blood and bones, just like you, is a very serious point that we are trying to put out, so that people can think of animals as sentient human beings, not just pieces of meat on supermarket shelves."

But the accusation against Peta is that it does precisely that — portray women as nothing but pieces of meat, even lower down the food chain than the animals it seeks to protect. Singh's response to this charge is revealing: "As a non-profit organisation we have limited resources. Not all men feel comfortable posing in skimpy underwear, and maybe more women feel sympathetic to our causes."

Men come in for abuse from Peta too. A recent campaign against fishing targets anglers by suggesting that they, by default, have small penises. A billboard on display in Aberdeen during National Fishing Month last year depicted a man holding a large fishing rod with the strapline, "Stop Fishing. DoAnglersHaveSmallRods.com"

Every year Peta produces a spoof of the State of the Union Address, re-branding it "the State of the Union Undress." This unfunny satire appears to apologise for terrorist tactics. Peta Vice President of Policy Bruce Friedrich is notorious for once telling an animal rights convention that "blowing stuff up and smashing windows" is "a great way to bring about animal liberation," adding, "Hallelujah to the people who are willing to do it."

What about the claims that Peta euthanises animals? "Well, we are not an animal shelter," says Friedrich. "If we did not euthanise those who are ill-treated they would suffer more in life, being chained to a fence or freezing to death."

According to public records from the Virginia Department of Agriculture and Consumer Services, Peta euthanised 2,124 pets in 2009 and gave fewer than ten to adoptive homes. Since 1998, a total of 21,339 dogs and cats have died in this way, making it more like a slaughterhouse than an animal rights campaign. It spends part of its $30 million-plus annual income on a contract with a crematory service in the US to empty periodically hundreds of animal bodies from its large walk-in freezer.