The price of flour is set to rise by another £25 a tonne before Christmas, as increased costs continue to hit the milling sector.

The major millers Rank Hovis and ADM Milling are preparing to announce a second round of price increases, just four months after they last put their prices up.

A Rank Hovis spokesman said it was striving to help customers mitigate increased costs. But year-on-year rises in energy and wheat prices meant a further £25 a tonne increase on flour prices was required, on top of the £29 a tonne increase it announced in August.

Price increases of £25 a tonne would add about 2-3p to the price of an 800g loaf.

The spokesman added: "It looks likely that we will have to build this into our plans in the short-term rather than after Christmas."

ADM Milling said it will announce another price rise soon, after it added £28.75 a tonne on its prices from September. A spokesman said: "Since announcing a price increase in August, UK bread wheat prices have increased by an additional 15%. World wheat stocks are at the lowest level for 25 years, and global demand is increasing. This is regrettably leading towards a further flour price increase in the next few months."

National Association of British and Irish Millers’ director general Alex Waugh commented: "A good part of the recent increases in wheat cost were in late September, some time after millers throughout the EU raised flour prices."

Frank Roberts bakery chairman Graham March said: "We do what we can to offset increases on input prices. But further flour price rises, together with high energy costs, would inevitably mean a price increase to the consumer."