New European regulations on labelling kosher meat will either lead to the end of shechitah or prices soaring, according to kosher butchers.
Jacky Lipowicz, chairman of the Licensed Kosher Meat Association, said the community could "lose everything" and urged shoppers to support a campaign launched this week by Shechita UK.
Promotional carrier bags, posters and stickers have been placed in kosher shops across the country urging people to press MEPs to vote against a change in consumer food information law.
The change, which the European Parliament backed in June, requires meat products from animals slaughtered by shechitah to be labelled as "meat from slaughter without stunning".
The measure will now go before the Council of the European Union at a meeting on December 7 and, if not voted out, will appear before the European Parliament for a second reading.
Shechita UK, the Board of Deputies, the Conference of European Rabbis and the European Jewish Congress, are working to lobby as many European politicians as possible. Campaigners say kosher prices could "rocket" because buyers from the non-kosher market, which takes 70 per cent of shechitah-slaughtered meat, may be put off by the labelling.
They also claim labelling is discriminatory because it requires only the meat from animals killed by religious methods to be labelled, rather than those killed by stunning, electrocution, captive-bolt or gassing. Mr Lipowicz said: "Labelling meat could lead to resentment in the non-kosher market where most of it is sold.
"People will stop buying it. If there is a backlash against the abattoirs, we could lose everything, which means no shechitah. If 70 per cent of the animal is not used, it could double the price of kosher meat. I feel there is latent antisemitism here and we have to fight it.
"They don't look at other methods of slaughter and we know shechitah is one of the safest and most humane ways of killing."
Mark Fitton, of abattoir J & B Fitton of Oldham, supplies meat to eight kosher licensees. He said: "From a cost point of view, the kosher market only provides a very small percentage so it won't be helpful if we have fewer customers who want to buy it.
"Some people from the non-kosher market might not want to have meat which has been ritually slaughtered but until we get a reaction, we don't know what will happen."
Shechitah has already been banned in Sweden, Iceland, Switzerland and Norway, and in New Zealand in May.
Henry Grunwald QC, chairman of Shechita UK, said: "While it's difficult to estimate what the net effect on kosher meat prices will be, it is clear that unless kosher consumers make their opposition heard loud and clear, huge numbers of the Jewish community will be priced out of the market.
"We must ensure that next Yomtov, there is still meat on the table."
Jon Benjamin, chief executive of the Board of Deputies, said: "The proposal is discriminatory. It presupposes that such meat is produced in circumstances that are somehow less favourable, when there is in fact plenty of evidence of the cruelty and suffering caused by slaughter involving pre-stunning."
Miriam Ollech, honorary treasurer of charity Keren Shabbos, which gives more than 240 kosher chickens to needy families in north-west London every Shabbat, said: "The price of meat will rise. For some this is their only protein and their way of putting something special on their table just once a week."
Rabbi Jeremy Conway, executive director of the London Beth Din Kashrut Division, said: "If we do nothing, this disastrous amendment could well become law, and have the most serious consequences for kashrut observance in communities across Europe."