Swine flu cannot be contained and the number of new cases could reach 100,000 per day by the end of next month, the Government said today.
The UK has moved past the stage of containing the outbreak and into the "treatment phase", Health Secretary Andy Burnham said.
"We have reached the next step in our management of the disease," he told the House of Commons.
"Our national focus will be on treating the increasing numbers affected by swine flu.
"We will move to this treatment phase across the UK with immediate effect."
There are now 7,447 laboratory-confirmed cases in the UK after a "considerable rise" last week.
In the UK three people - who all had underlying health problems - have died after contracting the virus.
Mr Burnham said: "Cases are doubling every week and on this trend we could see over 100,000 cases per day by the end of August."
The Government has signed contracts to secure enough vaccine for the whole population, he told MPs.
The first will become available next month, with enough for 30 million people to be vaccinated by the end of the year.
Under the new treatment phase, the Health Protection Agency will take a step back from dealing with the outbreak.
The daily updates on confirmed cases will end and "more general" estimates of numbers will be given.
Efforts to trace people who have been in contact with swine flu cases will stop and schools will not close when hit by the virus, unless particular circumstances make it necessary.
Anti-virals will only normally be offered as treatment, not for prevention, and pressure on GP and hospital services will ease as more people receive diagnosis and treatment via other routes.
Mr Burnham said this would initially be through the NHS website or the swine flu information line but would subsequently be via the National Pandemic Flu Service.
Scottish Health Secretary Nicola Sturgeon announced similar changes to the flu strategy at a briefing in Edinburgh.
Scotland's Chief Medical Officer, Harry Burns, said the country could expect one-tenth of the UK cases of swine flu - about 10,000 cases a day in Scotland by August.
Meanwhile the Government's Chief Medical Officer, Sir Liam Donaldson, said a vaccine was at an advanced stage of production and denied the outbreak was out of control.
He said: "We have the advantage of a centralised healthcare system which, when it needs to, can take control.
"We have a big stockpile of anti-virals, the biggest probably in the world."
The disease, he said was "following a predictable path - it isn't out of control, but flu viruses cannot be put back in their box once they are out".
Sir Liam said he could not currently give an expected mortality rate, but should be able to in the next few months.
Mr Burnham added: "We are in a strong position to deal with this pandemic. We are the only country in the world to be able to offer anti-virals to everyone as well as those at greater risks.
"People should be reassured and should not be alarmed by this change."
He said it was not yet known what the cost of tackling swine flu would be.
London and the West Midlands have already had enough cases to force health officials to adopt the policy of outbreak management.
Asked why certain areas had become swine flu hotspots, Mr Burnham suggested close family ties could be to blame.
:: There are three stages of swine flu management:
Containment: People with swine flu have their diagnosis confirmed by lab reports. They and anyone who has come into contact with them are given the anti-viral drug Tamiflu. Most parts of the UK are still in this phase;
Outbreak management: People are diagnosed by a health professional without the need for lab confirmation, and are given Tamiflu. Swabbing takes place only on a small sample of cases. People who have come into contact with a swine flu victim are unlikely to receive Tamiflu as a precaution;
Treatment: The detail of this phase is still being worked out. The Government envisages that not everybody with swine flu will receive Tamiflu, which may be reserved for at-risk groups.
The Health Protection Agency (HPA) today said laboratory tests have shown a further 458 patients in England have swine flu.
Taken with the 57 new cases in Scotland identified yesterday, another in Northern Ireland and four confirmed in Wales, they brought the total number of laboratory-confirmed cases identified in the UK since April 2009 to 7,447.
The worst-affected region is the West Midlands with 2,582 confirmed cases, followed by London with 1,939.Reuse content