BORIS Johnson has issued a final warning to the public to observe social distancing advice when outside or face “tougher measures,” raising the prospect of a much stricter Italy-style lockdown.

And as the coronavirus continues its remorseless rise - UK deaths rose by 47 to 281, including three more in Scotland – the UK Government set out an unprecedented plan to “shield” 1.8 million people across the UK with serious health conditions, including 200,000 in Scotland, by calling on them to stay at home for “at least 12 weeks”.

Addressing the daily Downing St press conference, the Prime Minister praised most people for observing the medical advice on staying home and observing social distancing when outside but, he noted, others were not and were congregating in a way that Jenny Harries, the Deputy Chief Medical Officer, described as “dangerous” because it was likely to spread the disease.

Over the weekend, thousands of people were observed congregating in parks and on seafronts, openly flouting the medical advice to keep two metres apart in public spaces.

Mr Johnson said it was crucial to physical health and mental well-being that people could enjoy parks and other open spaces but he noted: “If people can’t make use of parks and playgrounds responsibly, in a way that observes the two-metre rule, then, of course, we’re going to have to look at further measures.”

He went on: “I don't think you need to use your imagination very much to see where we might have to go and we will think about this very very actively in the next 24 hours.”

Four European countries have imposed stricter conditions on people leaving their homes. Italy has even banned its citizens from running and cycling. Yesterday, it prohibited all internal movement across the country other than urgent as its death toll rose by another 651 to 5,476.

Last night, Germany banned meetings of more than two people outside work and home for two weeks as Angela Merkel, its Chancellor, announced she was self-isolating after meeting a doctor on Friday who had since tested positive for the virus.

The PM said: “We need to think about the kind of measures we've seen elsewhere; other countries that have been forced to bring in restrictions on people's movements altogether.

“Now, as I say, I don't want to do that. It's so important that pleasure and that ability[to enjoy open spaces] is preserved but it can only really be preserved if everybody acts responsibly and conforms with those principles of staying apart from one another and social distancing.

"If we can't do that then, yup, I'm afraid we're going to have to bring forward tougher measures," he added.

More national parks and gardens across the country, including the National Trust, announced they were closing as, despite Government advice on social distancing, good weather and Mother's Day celebrations continued to draw large crowds to the attractions at the weekend.

The British Holiday and Home Parks Association has contacted its members who run some 2,900 holiday and touring parks across the UK to strongly advise them to close with immediate effect to all holiday visitors.

Earlier at her media briefing at St Andrews House in Edinburgh, Nicola Sturgeon addressed how, while a majority of pubs and bars in Scotland had observed the advice to close, a “tiny majority” on Saturday had not.

"Let me be blunt; in doing so, they put lives at risk. My message to them is: close now. We will have emergency powers in days to force you to close and we will use these powers if we have to," declared the First Minister.

The emergency Coronavirus Bill, which is set to pass through Westminster and get Holyrood’s consent by the end of this week, will give police much stronger powers to act.

However, Malcolm Graham, the Deputy Chief Constable of Police Scotland, revealed he had obtained further legal advice, which meant the force could take immediate action; officers would visit premises on Sunday to have them closed, he said.

“Police Scotland will now instruct officers to serve emergency closure orders on any licensed premises which refuses to comply on the grounds of the threat posed to public safety,” explained Mr Graham.

"A compulsory closure under the Licensing Scotland Act remains in place for 24 hours but can be repeated as necessary," he said, noting how police would also report such pubs and bars to the relevant Licensing Board for further action to be considered.

The police chief denounced the flouting of the medical advice as “absolutely reckless,” saying it “endangers not only the lives of customers, but wider communities, in an extremely fast moving and unprecedented situation where both the health and safety of the nation is at stake”.

At her press conference, Ms Sturgeon also announced that Scotland's islands were to become a no-go zone for visitors, announcing ferry companies had been told not to take "non-essential travellers".

It came as the SNP Government revealed it had to call on military help to transport a patient from one of Scotland's islands to the mainland for treatment.

As schoolchildren across Britain prepare to stay away from school, the FM also explained how senior pupils who had been planning to return to school despite closures to complete coursework for exams had also now been told to stay away.

On shielding the clinically vulnerable, Robert Jenrick, the UK Communities Secretary, told the No 10 press briefing: “In recent weeks, heroic workers in the NHS, social care and public services in local government have been shouldering the country's burden.

“We owe it to them and the most vulnerable in society to stay home, to protect the NHS and, by doing this, to save lives. And so today we have to go further to shield the most clinically vulnerable people to help save their lives."

The call was for 1.8m people with serious conditions like cystic fibrosis and blood cancer to stay at home for at least three months.

“I don't underestimate what we're asking of people; It will be tough,” declared Mr Jenrick. "But if you are one of these people I want to assure them, on behalf of the Government, you are not alone."

He explained the Government would, with the help of military planners, be creating a network of local hubs to deliver medicines by pharmacists to the most vulnerable and lonely people. Groceries would be delivered by councils working with supermarkets with "parcels left on the doorstep". Members of the public could volunteer to help too.

"Nobody needs to worry about getting the food and essential items that they will need," insisted the Secretary of State.

Ms Sturgeon said an estimated 200,000 people in Scotland considered vulnerable would have to “strictly isolate” but made clear that a similar support network to help them in receiving food and other essential supplies would also be established north of the border.

At her press conference, the FM stressed that “no corner of Scotland is not at risk of seeing some of their residents die” from coronavirus.

She added: "However, if we all do the right thing now, we will reduce that impact and save lives. If we don't, we face many more people than would otherwise be the case becoming ill and dying and we risk our NHS being overwhelmed.

"I am not saying this to scare people, I am saying this to leave you in no doubt about the seriousness of the situation we face."

At the weekend, Professor Jason Leitch, the National Clinical Director, noted starkly that heeding the medical advice not to go out unless necessary and to observe social distancing could be "the difference between tens of thousands of deaths and the number of around 2,000" in Scotland.

Globally, the number of coronavirus cases has passed 310,000 with more than 13,500 deaths.

Spain has extended its state of emergency for a further two weeks after it recorded 400 deaths in a day, the highest daily number.

But China, where the virus began, has recorded its fourth day without locally infected cases.

Meanwhile, KPMG, the global network of tax experts, today suggested coronavirus would bring the UK economy to a temporary halt. In its quarterly economic outlook, it forecasts a 2.6 per cent decline for 2020 with flat growth predicted in second half of year.

But it warned that a more protracted outbreak could also result in a more severe impact than the 2008 financial crisis with a 5.4 per cent fall in growth.

In other developments -

*Mr Jenrick insisted “good progress” was being made in kitting hospitals out with personal protection equipment to treat virus victims after doctors and nurses complained that they were being used as “cannon fodder,” saying PPE was not being provided quickly enough.

*The Government has announced a £20 million investment in a new genome sequencing consortium to map the spread of coronavirus that will provide a “unique, cutting-edge tool” to combat Covid-19.

*Mr Jenrick said the Government was reviewing the situation as regards helping self-employed people as more than 2,000 musicians wrote to Rishi Sunak, the Chancellor, demanding more assistance in the face of the outbreak. Signatories to the letter included musicians from the BBC Symphony Orchestra, Royal Ballet, bands from West End musicals and the band Simply Red.

*The Foreign Office said hundreds of British nationals stranded in Peru due to the pandemic could be flown home early this week and

*ITV announced it would "suspend production" on Coronation Street and Emmerdale from Monday.