When people are displaying symptoms, they should contact the NHS by phone, the government said.
If doctors believe the person is suffering from swine flu they will be told to stay at home and be given a voucher which a friend or family member can take to a drug collection point, such as a pharmacy.
But GPs will have the discretion not to prescribe anti-viral drugs.
Some experts believe the drugs should just be targeted at the most vulnerable as the virus is quite mild and overuse can lead to resistance.
Ministers rejected this option, but said doctors may want to limit use in certain situations such as where patients are suffering milder symptoms.
The need for lab testing had already been lifted in several hotspots, such as London and Glasgow.
But the rest of the UK had been operating a containment strategy, which meant cases had to be confirmed and drugs were also offered to close contacts in a bid to prevent flu developing.
It also led the closure of several schools. This will still be an option under the new phase, but shut downs will not be routine.
Andy Burnham, the health secretary in England, said: "The national focus will be on treating the increasing numbers affected by swine flu.
"Cases are doubling every week and on this trend we could see over 100,000 cases per day by the end of August."
But he said the attempts to contain the virus had been worthwhile.
"Our efforts during the containment phase have given us precious time to learn more about the virus."
I should stress that this is not a sign that the virus is getting more virulent. It is an admission that the spread of the virus can no longer be contained
He confirmed vaccines should be available from next month, with 60m doses available by the end of this year.- enough for 30m people.
Enough vaccine to cover the whole UK population is in order.
Scottish Health Secretary Nicola Sturgeon announced similar changes to the flu strategy at a simultaneous briefing in Edinburgh.
She said: "We've always said it would be impossible to limit the spread of what is a contagious virus indefinitely."
There have been more than 7,000 confirmed cases in the UK since the first outbreak in April. In England, 458 more cases were reported on Thursday.
Three people have died, but all had underlying health problems.
However, it is thought there will have been a number of people who did not get a formal diagnosis because their symptoms were so mild.
Both the Tories and the Liberal Democrats backed the move to the new phase but both parties expressed concerns that not all parts of the government's pandemic plan - including the dedicated flu helpline - were in place.
The announcement comes as a survey by London's Institute of Psychiatry finds the public's response to swine flu has been "muted".
A poll of 1,000 adults, published online by the British Medical Journal, found only 24% were anxious about the outbreak with only 2% reporting "high anxiety".
Three quarters said they had not changed the frequency with which they washed their hands, despite this being one of the core messages of the public health campaign.
However the researchers say their findings suggest it is better to keep the public as informed as possible in order to maximise the chance they will make changes to their behaviour.
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