Agricultural workers are appealing to peers to halt the government's plan to take millions of pounds out of their pockets by scrapping the body that regulates their wages.
Unite hopes to have the vicious scheme stopped in its tracks in the House of Lords.
The Agricultural Wages Board (AWB) is the last of the wage councils set up after the second world war to regulate pay and conditions - the others were axed in the early 1990s.
Agricultural workers suffered low pay and long hours, and the "tied" cottage system meant many workers' homes were dependent on their employment.
Today 150,000 agricultural workers are dependent on the graded AWB minimum wage.
Shortly before Christmas the government quietly confirmed its intention to press ahead with the abolition.
The proposal has to get through the House of Lords, and Unite is lobbying Labour and Lib Dem peers urging them to reject the proposal, which is debated on Wednesday.
Unite national agriculture officer Julia Long said: "Many peers share our sense of outrage, both at the government's plan to decimate rural workers' livelihoods, and at the underhand and dishonourable way in which it has been done.
"The AWB's abolition will take £247 million out of the pockets of agricultural workers in the next 10 years, according to the Department for Environment, Food and Rural Affairs' own figures.
"The beneficiaries from such a move are clear - the big agri-business bosses and the major supermarkets hell-bent on driving down workers' wages to poverty levels."