Supermarket price wars have reduced the average retail price of a four-pint bottle of milk by 12% in less than nine months.

On average - across a wide range of retailers including the top five mults, discounters and symbol groups - the price of a four-pint unit has fallen from £1.29 in February to £1.14 by 8 October, according to new research conducted by ESA Retail for AHDB and DairyCo.

And these figures were calculated before Iceland announced this week that it was slashing its price for four pints of milk from £1 to 89p amid ongoing dairy commodity market volatility and farmer ­protests over low farmgate prices.

Iceland’s decision provoked anger on social networks, with the retailer accused of a “revolting underselling of a high-quality product” by one Twitter user, while another claimed the new 89p price was “not something to be proud of”.

Iceland said it had not reduced the price it paid for milk, and had little influence over the price farmers received. The retailer claimed it needed to ­”differentiate itself from the ­competition and offer the best deals it can to its customers”.

DairyCo said consumers were showing a growing preference for lower prices over multibuys, allowing them to manage their spend and reduce wastage. Retailers continued to see milk as a key focus of their communication on basket prices despite the current climate at farmer and processor level, said DairyCo communications head Amanda Ball.

The issue went beyond the retail price war on milk, she added. Noting the UK’s ­significant trade deficit in dairy, which increased by £91m to £1.36bn last year, Ball urged consumers to buy British cheese, butter and yoghurt to help mitigate the industry’s current woes. Four pints can currently be bought at the major mults for £1.