Shares in the maker of Mr Kipling and Bisto are diving after a warning about the collapse of the pound

LONDON - Shares in Premier Foods, the manufacturer of high street brands like Mr Kipling cakes, Bisto gravy, and Ambrosia custard, are plummeting on Wednesday after it issued a major profit warning.

Premier warned that it's full-year profits are likely to be as much as 10% lower than previously forecast after a terrible third quarter, with sales in the quarter falling 1% to £251.4 million.

The company has already increased prices since the Brexit vote, citing increasing costs linked with the plunge in the value of sterling following the referendum. However, cost increases have not helped so far, if today's results are anything to go bad.

"Sales in our third quarter were weaker than expected despite a strong December. We now expect category performance to remain challenging during the fourth quarter and as a result, sales will be below previous expectations," CEO Gavin Darby said in a statement accompanying the results.

"Additionally, recovery of significant input cost inflation in certain areas is taking longer than originally foreseen. Consequently, we now expect Trading Profit for FY16/17 to be approximately 10% below previous expectations."

As a result of the news, the company's shares - which trade on the FTSE Small Cap Index - are crashing, falling more than 16% in early morning trade.

Here's how shares looked just before 8.30 a.m. GMT (3.30 a.m. ET):