A UK report concludes that 10 per cent of sausages sampled were found to contain Hepatitis E and there is “increasing evidence’ that hepatitis E is a foodborne infection.

The infection was once considered very rare but cases have risen by nearly 40 per cent in a year and there were 657 in 2012.

The virus usually causes only relatively mild symptoms such as sickness, a temperature and muscle pain, which clear up by themselves within a month.

But it can be fatal for the elderly, cancer victims, pregnant women and others with existing liver problems.

Around one in 50 of those infected will die, rising to one in five pregnant women.

Experts say sausages have to be cooked at 70C (158F) for at least 20 minutes to kill the virus but they say that most Britons do not leave them in the oven for this long.

Tests have showed that it can survive at 60C (140F) after an hour.