Britain's Prime Minister Boris Johnson on Thursday said he was confident the country can slow the spread of coronavirus in the next three months through tough measures to cut social contact.
The government earlier this week called for more people to work from home, and avoid public transport, pubs, clubs and restaurants, to try to slow infection rates.
The UK death toll has risen to 144, and the government has unveiled plans for emergency powers to deal with the spiralling outbreak, including forced testing for suspected cases.
But Mr Johnson said he was "absolutely confident" the situation could be improved, depending on "resolute, determined, collective action", as well as more testing and diagnostics.
"I do think, looking at it all, we can turn the tide within the next 12 weeks... but only if we all take the steps that we have outlined,” he said.
"That's vital. That's how we are going to reduce the peak."
Asked about his reasoning, he conceded: "I cannot stand here and tell you that we will have by the end of June, that we will be on a downward slope. It's possible.”
"But I simply can't say that that's for certain. Of course not. We don't know where we are and we don't know how long this thing will go on for.”
"But what I can say is that this is going to be finite. We will turn the tide and I can see how to do it within the next 12 weeks."
Britain does not currently routinely test for anyone displaying COVID-19 symptoms and instead recommends people stay at home to protect the elderly and those with existing health conditions.
Latest health ministry figures said there were 3,229 confirmed cases but government chief scientific adviser Patrick Vallance has said a "reasonable" estimate was that 55,000 had the virus.
Mr Johnson said talks were under way to buy "literally hundreds of thousands" of antibody testing kits as soon as possible, to determine who had already contracted COVID-19 but recovered.
"Obviously it has the potential to be a total game changer," he told reporters.
Tube stations closed as London lockdown looms
Transport officials in London closed dozens of Underground stations on Thursday, as the city tries to stem the outbreak of the coronavirus pandemic.
The move to close up to 40 stations, alongside other measures to scale back public transport across London, came as the government placed 20,000 troops on standby to help in the fight against COVID-19.
"People should not be travelling, by any means, unless they really, really have to," London Mayor Sadiq Khan said.
"London will get through these extraordinarily challenging times, and ensuring the capital's critical workers can move around the city will be crucial."
Londoners are bracing for further measures and on Wednesday evening, the Ministry of Defence said 20,000 military personnel were being placed at "higher readiness" to help public services.
A closed Underground station at Covent Garden in London, Britain, 19 March 2020 Source: EPA
Reservists would be called in and 150 military personnel trained to drive oxygen tankers to support the health service if needed, defence minister Ben Wallace said.
If you believe you may have contracted the virus, call your doctor, don’t visit, or contact the national Coronavirus Health Information Hotline on 1800 020 080.
If you are struggling to breathe or experiencing a medical emergency, call 000.
