Sausages have soared up to 50% in price over the past year thanks to constricting UK and EU pork supplies and the weak pound.

The average price of a six-pack of branded sausages in the big four last month was £2.09 - up 50% on last year, while the price of own-label sausages was £1.16 - up 37% on a year ago, the latest data from The Grocer 33 has revealed.

Analysts say the declining UK and EU pig herds, combined with greater demand for European pork from China, have hit prices hard in the £430m UK sausage category.

UK pig herd numbers were down 9% year-on-year in March, with weekly slaughterings falling from 175,000 in March 2008 to 159,000 last month, according to Bpex. EU production is also falling as farmers quit the sector blaming poor returns.

Meanwhile the Chinese pig herd has been hit by an outbreak of blue ear disease, which has led to Chinese supermarkets sourcing more pork from Europe. Retailers were forced to pay higher prices to guarantee supplies, said one sausage supplier. The rising cost of rusk had also led to increases.

"All these factors, plus the higher feed prices and the fact that supermarket pricing on sausages hadn't changed for many years, have all come together at the same time," he said.

A further complication has been the fall of sterling. With the UK importing at least half the pork eaten in this country, the cost of producing sausages has gone up.

Prices were likely to stay high in the short term, said Bpex senior economic analyst Tony Fowler.

"Producer prices are at their highest since 1996," he said. "For the first half of this year we would expect UK production to be quite low so prices will remain firm."

While supermarkets were still keeping the cost of promotions low, with the price of sausages on promotion only rising 36p/kg in the big four, non-promotional sausages had gone up an average of 63p/kg, according to AHDB figures.