The UK lags behind many other European countries in treating hepatitis C and without urgent action thousands could die prematurely, a charity says.
The virus is carried in the blood
The Hepatitis C Trust called for new screening targets, estimating 500,000 UK people had the virus, which attacks the liver, but only one in seven knew.
It compared the situation in the UK with France, Germany, Italy and Spain.
The government said it recognised the blood-borne disease as a priority and had a clear UK framework for action.
However, the trust believes this is not enough.
According to the charity, the UK has the lowest percentage of people with hepatitis C being treated compared with the four other European countries it looked at.
Only 1-2% of those with the disease in the UK had been identified and treated with approved drugs, which can cure between 60-80% of those treated, it said.
At least five times more people in France are likely to receive treatment than in the UK, said the trust.
Italy, Spain and Germany are also better at diagnosing and treating people with hepatitis C, it added.
The Hepatitis C Trust's chief executive, Charles Gore, said: "The government needs to make hepatitis C a priority.
"We have a dreadfully poor track record at diagnosing the disease.
"Over 400,000 people in the UK with the virus are completely unaware they have been infected.
Lessons from France
"As a consequence, they are not in a position to make lifestyle decisions that could reduce liver damage and may inadvertently be putting others at risk of infection."
Professor William Rosenberg, lead author of the report from the University of Southampton, said: "If we catch it in time, the virus can be treated with drugs that cure 40-80% of those infected.
RECOMMENDATIONS BY THE TRUST
Set targets for screening and treatment
Increase public awareness
Improve care delivery
Work on rapid referrals
"We have no time to lose. We need to learn what countries such as France have done to successfully manage the disease."
The French government ran annual awareness campaigns and set a target of screening 85% of at-risk populations by 2003.
Such measures have led to better detection and a significant reduction in deaths, said the trust.
Hepatitis C is usually passed on by intravenous drug use, but can also be spread through tattooing, body piercing, acupuncture or through blood transfusions carried out before screening for hepatitis C began in 1991.
People can be infected with the virus for more than 20 years before symptoms develop.
Up to a third of those who are infected will go on to develop severe liver disease, which may prove fatal if they do not receive a liver transplant.
The Department of Health said in a statement: "The Chief Medical Officer has already highlighted treating hepatitis C as a public health issue in his infectious disease strategy.
"We have set out a clear national framework for action and provided support for raising awareness and improving surveillance, which are a key factor in improving prevention, diagnosis and treatment.
"We have also asked primary care trusts and their local partners to ensure that local arrangements are in place to provide appropriate services."