West Country dairy farmers will deliver a petition to Downing Street on Tuesday at 10.30am, demanding a government inquiry into the activities of supermarkets, which many farmers believe are operating a cartel and forcing them out of business. The Great Milk Robbery campaign – organised by Devon Young Farmers – has been surveying supermarket customers around the south west while dressed in large cow costumes. Now, they will present these results to Number 10, demanding the government acts against supermarkets that are forcing prices so low that many farmers are making a loss, and eventually leaving the business. The campaigners will be joined by Conservative MEP and Tory agriculture spokesman Neil Parish, who was a dairy farmer before entering politics. Farmers now get an average of 18p a litre for milk which sells for 51p in supermarkets, but the cost of production is put officially at 21p. More than 1,000 dairy farmers have quit in the past year and campaigners say the total will continue to grow unless the government intervenes. Campaign organiser Sally Dare said: 'Unless dairy farmers get a better price for their milk soon, the industry will collapse and we will be forced to import most of our milk. 'Dairy farmers simply cannot go on producing milk at a loss. 'We believe supermarkets are operating a cartel. The government should take action to expose this, and clamp down on unfair practices. 'When we surveyed supermarket customers, we found most would be more than happy to pay a few extra pence for their milk if they thought it would keep the dairy industry afloat. 'Unfortunately, the profits are going straight to the supermarkets, rather than the farmers.'