LONDON -- Police arrested a protester Monday after he interrupted a campaign event held by British Prime Minister Theresa May. "Save our wildlife, kill May" the protester shouted as the prime minister arrived at a rally in Wales.

The man was protesting fox hunting, which May's government has promised to bring back up for a vote should her Conservative Party win national elections on June 8 to remain in power.

The bloodsport, which was a mainstay of British upper-class society for hundreds of years, was banned 12 years ago.

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As the Conservative's election manifesto, the official party document laying out their policy proposals, is scrutinized, another contentious wildlife policy has emerged -- or rather, disappeared.

The previous British government, also led by the Conservative Party, or the Tories, as they are commonly known, maintained an official policy of working "for a total ban on ivory sales."

The Independent newspaper reports that Mrs. May's manifesto has quietly dropped that line, and replaced it with a generic call for the protection of endangered species.

At the heart of the debate is the multi-million-dollar illegal trade in ivory, mostly taken from African elephants by poachers who leave the animals to die. As CBS News' Holly William reported, the trade is making the poachers and traders rich, but so many elephants are being slaughtered that scientists warned in 2014 the species could be completely wiped out within 100 years.

According to that study, 100,000 elephants were killed for their tusks over the course of just three years, and more contemporary estimates suggest as many as 20,000 are killed for their ivory every year.

Since 1979, the African elephant's range has shrunk dramatically. The animals have reached what the study's authors call a tipping point -- with more elephants killed each year than there are born.

Any sale or purchase of newly-poached ivory is strictly against the law, including in Britain, but a loophole in British law makes trade in "antique" ivory items (created in 1947 or earlier) legal. According to the Independent, lax verification required by the law to prove an item's age makes it difficult to enforce.

For that reason, the previous Tory government policy was to close the 1947 loophole and make all ivory trade illegal – a policy backed by conservation and animal welfare groups.

The director of PETA, Mimi Bekhechi, told The Independent that her organization would keep pushing for an outright ban.

"As long as animals continue to be beaten into performing in circuses, slaughtered for their ivory, or face being torn apart on fox hunts, PETA will continue to stand with the majority of the British people and urge any future government to do the right thing, whether it pledges to do so in its manifesto or not," she told the newspaper.

May's Tories have a solid lead over Jeremy Corbyn's rival Labour Party in the polls ahead of the June 8 vote, but the margin has narrowed slightly in recent days.

A significant diversion from a manifesto pledge -- on funding for elderly care -- announced by May on Monday in Wales threatened to further erode her comfortable lead.