LONDON — Britain faces a projected 100,000 new swine flu cases a day by the end of August and must revamp its flu strategy, the nation's health minister said Thursday.

Britain has officially reported 7,447 swine flu cases and three deaths, but officials acknowledge the real number of cases is far higher, since many with the virus have not been tested.

Britain is the hardest-hit nation in Europe amid the global swine flu epidemic. Many flu experts believe numbers could jump exponentially now that the virus is entrenched. Because swine flu, or H1N1, is a new virus, few people have any natural immunity, allowing the virus to spread rapidly.

"Cases are doubling every week and on this trend we could see over 100,000 cases per day by the end of August," Health Minister Andy Burnham told the House of Commons on Thursday.

Britain has been reporting several hundred new swine flu cases daily for the last several weeks. If that surges to 100,000 cases a day by the end of August, there could be 6 million people infected by the fall, or 10 percent of Britain's 60 million population.

Since flu spreads more quickly in densely populated areas, cases will probably be concentrated in cities like London, Birmingham and Manchester.

Britain had been trying to contain the disease by liberally giving out the drug Tamiflu to all suspected swine flu cases and their contacts. Yet many experts have criticized Britain's attempt to contain the outbreak, saying it wastes resources, drugs and could promote antiviral resistance.

Burnham said Britain will now only give the antiviral to people believed to have the virus.