England is trying a radical experiment which every other government will watch closely.
Broadly, there is a choice for policy-makers: either go for mass vaccination early and then open up society or, on the other hand, lock society down and keep infections low by preventing people coming in contact with each other.
Australia has chosen the second: lockdown. Britain is going for the first: vaccinate and open-up course - and in a big way.
If it works in England, the Australian government's policy of severe lockdown (and lockout of outsiders) will seem more like a mistake.
Vaccinating lots of Australians earlier would have served us better.
If the English experiment doesn't work - say because the number of serious cases of Covid overwhelms hospitals - then we are all in for a much longer haul. Lockdowns until a very high proportion of people are vaccinated will be the way, and it may not work even then.
So what is England doing?
From July 19, England (but not the other parts of Britain like Wales, Scotland and Northern Ireland) will have its coronavirus restrictions lifted, even though infections are currently running at the rate of more than 30,000 new cases a day.
In the last few days in Australia, there have been just over 100 new cases each day.
"We will move away from legal restrictions and allow people to make their own informed decisions about how to manage the virus," British Prime Minister Boris Johnson said.
- There will be no limits on how many people can meet;
- Masks not required by law;
- Nightclubs can reopen;
- No limits on numbers at concerts, weddings, funerals, churches;
- Under-18s and fully-vaccinated adults can travel abroad except to the worst-hit countries without quarantine on return;
- From August 16, schools will resume; and
- Fully-vaccinated adults won't need to self-isolate if they come into contact with an infected person.
"Guidance" will remain. The government hopes people will do the right thing like wear masks, particularly on public transport, but there will be no penalties for not doing so.
People are advised to meet others outside where possible.
Nightclubs and concert venues may ask for proof of vaccination before entry. In effect, a vaccination passport.
Three-quarters of the population of Britain have had at least one dose of a vaccine and just over half have had the full two doses. In contrast, about one-quarter of Australians have had at least one dose and only 10 per cent have been fully vaccinated.
Because of this, the reasoning is that looser restrictions will not lead to a big rise in serious cases, requiring hospitalisation.
The British prime minister believes this means a more voluntary approach is justified.
"We will move away from legal restrictions and allow people to make their own informed decisions about how to manage the virus," Mr Johnson said.
The implication is infections may well rise but the country can cope. Just as with the flu, vaccinated people will mostly be spared the worst effects. Casualties will be a price to be paid for freer lives.
The pro-Johnson tabloids call July 19 "Freedom Day".
In contrast to Australia, a substantial proportion of the British population has had two doses of the vaccine.
In the initial, pre-vaccine wave of the pandemic a year ago, the great fear was the number of seriously ill people would be so great health systems would simply not be able to cope. Emergency units in hospitals would be overwhelmed and people would die untreated.
Mr Johnson said that would not happen this time. "Scientists are absolutely clear that we have severed the link between infection and serious disease and death," he said.
"Currently there are only a 30th of the deaths that we were seeing at an equivalent position in previous waves of this pandemic."
On top of that, the emerging evidence was vaccination prevented many people - but not all - actually catching Covid (and not just catching it without symptoms).
'Dangerous and unethical'?
Fifteen scientific experts wrote in the highly-respected Lancet journal deploring Mr Johnson's experiment in strong terms.
"We believe the government is embarking on a dangerous and unethical experiment, and we call on it to pause plans to abandon mitigations on July 19, 2021," they wrote.
They spelled out their reasoning: "Population immunity is unlikely to be achieved without much higher levels of vaccination than can be reasonably expected by July 19, 2021."
They said tight regulations about social distancing and mask-wearing, for example, remained necessary: "Proportionate mitigations will be needed to avoid hundreds of thousands of new infections, until many more are vaccinated.
"The link between infection and death might have been weakened but it has not been broken."
This is not just a matter of science. Politics also plays a big role.
Mr Johnson has calculated people will do the right thing and that, if they don't, large numbers of infections will be tolerated in return for an easing of restrictions.
But the political situation may well be different in Australia, where opinion polls have shown strong support for the closing of the international border. Lockdowns are politically popular.
Fifty-seven per cent of Australians have passports compared with 75 per cent of the British population.
Far more British people go abroad for holidays than do Australians. Broadly, before Covid, about two-fifths of Australians went abroad for a holiday each year compared with three-fifths of the British.
British people have become accustomed to summer holidays in Greece or Spain and short weekend city breaks across Europe.
The experiment was very high risk. What happens if serious infections soar and there is an outcry about rising deaths but also a hard reluctance to re-accept restrictions?