BORIS Johnson will today consider ordering a wider lockdown of the country as he comes under mounting pressure to do so after thousands of people flouted the medical advice on social distancing to slow the increasing spread of the coronavirus pandemic.

Matt Hancock, the UK Health Secretary, insisted "nothing is off the table" in terms of the future action which could be taken, saying: "I do not want to pre-judge the discussions we will have today to make a decision on those things. Ultimately, it is a decision for the Prime Minister.

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"I advise him on what I think needs to happen and I am really clear, people need to stay more than two metres apart. We have got to see that happen because that is the only way to protect life."

Asked why people were ignoring the advice for social distancing, the Cabinet minister told BBC Radio 4's Today programme: "I don't know, because it is very selfish. The NHS is doing everything it can and preparing for the spread of this virus.

"If people go within two metres of others who they don't live with, then they are helping to spread the virus and the consequence of that costs lives and it means, for everyone, this will go on for longer.”

Mr Hancock added: "Until we get a grip on the spread of this virus with the kinds of measures we have taken, then we can't start to get our way out of it as a country."

Mr Johnson is said to be facing a “full-scale mutiny” of his Cabinet if he does not force a full lockdown in London, the epicentre of the UK outbreak. Pictures were posted on social media this morning showing crammed Tube trains.

Finn Brennan, a district organiser for train drivers' union Aslef, said drivers and front-line staff were “furious” at the early morning crush on London Underground.

He tweeted: "Still heavy loading on some Tube lines this morning making social distancing impossible. This is endangering the health of the vital workers who have to use the system.

"The Government must act now to ensure only ESSENTIAL journeys are made,” he declared.

Julian Smith, the former Northern Ireland Secretary, said he would support "any measure" the Government brought forward to force people to comply with the guidance.

Jonathan Ashworth, the Shadow Health Secretary, said ministers should be making "immediate preparations" for the "next stage" while learning from other European nations, where there have been stricter lockdowns on people’s movement and travel.

The calls for stronger action came as an 18-year-old was thought to have become the youngest victim of the virus in Britain as the number of deaths in the UK rose to 281.

In Walsall, Areema Nasreen, a 36-year-old nurse and mother-of-three, is on a ventilator in intensive care after contracting coronavirus. She is in a critical condition at Walsall Manor Hospital in the West Midlands where she works.

There are growing fears that Britain is on a similar trajectory to Italy - scene of the world's worst outbreak - where the death toll passed 5,000 over the weekend.

The Italian Government was one of a number of European countries to announce new or extended restrictions; Germany yesterday banned public gatherings of more than two people not from the same household.

Mr Hancock has admitted there have been "challenges" with the supply of personal protective equipment[PPE] to frontline NHS staff after a doctors' leader said they felt they were being treated like "cannon fodder".

Amid reports that a number of medics are seriously ill after becoming infected with Covid-19, the Health Secretary said the armed forces were being drafted in to help distribute PPE supplies to the health service.

Meanwhile, respiratory doctors and nurses at Belfast Trust launched a video on Twitter saying people should stay at home to save lives.

One medic there says she has been a doctor for 35 years, adding: "I'm Susie, we are facing our greatest challenge and we are frightened...Please stay at home."

Mr Johnson has warned that the NHS could be "overwhelmed" in the same way as the Italian healthcare system has been, if the spread of the virus in the UK is not curbed.

But at his daily No 10 press conference on Sunday, Mr Johnson indicated he was reluctant to ban people from going outside for a walk or to exercise because of the physical and mental health benefits, as long as they acted responsibly.

The Government later issued updated guidance making clear that essential travel did not include visits to "second homes, camp sites, caravan parks or similar, whether for isolation purposes or holidays".

However, among some MPs there was a clear mood for firmer action amid fears that further delay would cost lives.

Mr Smith said: "Many people have recklessly ignored Government advice this weekend. I will support any measure the Government needs to force people to follow the guidelines designed to protect NHS staff and UK citizens' lives."

For Labour, Mr Ashworth said: "We urge the Government to make immediate preparations for the next stage and learn lessons from other European nations.

"If voluntary social distancing measures are not adhered to, the Government must bring forward their plans for stronger action."

His Labour colleague Rosena Allin-Khan, who also works as an A&E doctor at St George's Hospital in south London, also bitterly attacked the Government's approach.

She said her latest shift had been a "deeply, deeply eye-opening" experience with previously fit and healthy people in their 30s and 40s "attached to machines, fighting for their lives".

"The Prime Minister has been blase about this from the start, waiting for others to make decisions so he doesn't have to. It is costing lives," she declared.

"Enough is enough. The NHS cannot cope and it won't be long before doctors have to choose between who lives and who dies."

While people were heading to open spaces, there were signs that city and town centres were closing down with Nando's, Costa Coffee, McDonald's, John Lewis, Primark and Timpson among the high street chains to announce they were closing their doors.

Meanwhile, letters are today going out to 1.8 million people with underlying health conditions – including 200,000 in Scotland - who are considered to be the most vulnerable to the coronavirus telling them to stay at home for at least 12 weeks.

The Government said it would ensure those without families and friends to support them would continue to receive food and medicines, with the military helping to organise deliveries.

Schools across the country today will be opening their gates only to the children of key workers considered essential to the running of the country, with apparent confusion over how many will be admitted.

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Gavin Williamson, the UK Education Secretary, appealed to parents to keep their children at home unless their job was "critical" in the response to the coronavirus.

"This will help to halt the spread of the virus, protect the NHS and save lives. We will be closely monitoring what is happening in schools and will ensure they get the support they need in the weeks and months ahead," he said.