Groups of dairy farmers have been emptying milk from supermarket shelves across the country in protest at the price paid for milk.

The protest, dubbed the Milk Trolley Challenge, sees protesters removing all cartons of milk from shops including Morrisons and Lidl and either paying for it and taking it away or dumping it at the checkout.

Arla, Britain’s biggest milk co-operative, has announced a price cut of 0.8p per litre – taking the standard litre price to 23.01p for its UK members.

Farmers say it costs between 30p and 32p to produce each litre of milk, according to British dairy organisation AHDB Dairy.

Meurig Raymond, president of the National Farmers’ Union (NFU), said: “The market situation in dairy, lamb and many other products is driving farming families to a desperate state with returns from the market failing to cover costs of production.

“Farmers have worked very hard to gain the respect and support of the public for great British food - now farmers simply want and need a fair return for years’ of investment.

“Given the current situation some farmers have been driven to take direct action; the NFU supports protests that have a proper target and a clear objective.

“However, we believe that the best way for farmers to get a fairer return would be for consumers to demand British food.

“Our survey work has shown that 85% of people want to see retailers selling more British food. Now is not the time to alienate our loyal customers.”

Figures published by AHDB Dairy show the average UK farmgate price was 24.06p per litre in May, a decrease of 25.4% of the amount paid to farmers in May last year.

A spokesman said: “Anecdotally, farmers are putting the costs of production at around 30/32 pence per litre, which demonstrates that for some, the price they receive will not cover what it costs them to produce the milk.”

Darren Blackhurst, Morrisons’ group commercial director, said reduced global demand had created an oversupply of British milk, creating “difficult conditions” for many dairy farmers.

“At a constructive meeting on Wednesday with the NFU Dairy Board chairman, we confirmed that Morrisons is not accepting any further cost price decreases from our suppliers driven by the falling farm gate milk price,” he added.

A spokesman for Lidl said the supermarket worked closely with farm assurance schemes such as Red Tractor and RSPCA Freedom Food to champion British farming.

“Naturally, we are concerned about the challenges faced by British farmers currently as a result of volatility in global market conditions,” she added.

“As such, we have pricing mechanisms in place which are monitored at regular intervals during the contract period to reflect market fluctuations and to ensure that our farmers continue to be paid a fair and accurate market price.

“Our cost prices are in no way linked to our retail prices and any reductions in retail prices are absorbed by Lidl.”