The government would consider an Italian-style lockdown if people fail to follow advice to stay at home during the coronavirus crisis, a senior minister has said.

Robert Jenrick, the communities secretary, failed to rule out bringing in stricter enforcement measures to keep the public at home amid reports of crowds in parks and at seaside resorts.

It comes as Boris Johnson urged the public to resist visiting their parents on Mother’s Day, warning that the Covid-19 outbreak is “accelerating” in the UK.

GPs are writing to more than 1.5 million people with underlying health conditions to urge them to stay at home for up to three months, with military planners drafted in to help local support systems.

“We want to live in a free society where we can continue to go about activities while following the medical advice. But this isn’t a game, it is very serious,” Mr Jenrick told Sky News’s Sophy Ridge on Sunday.

“If people don’t follow that advice, we’ll clearly have to follow other options, but none of us want to go down that route.”

He said the images from Italy were “sobering” and urged Britons to follow the medical advice to help “turn the tide” on the coronavirus crisis.

In a direct message to the vulnerable people who should stay home, Mr Jenrick said: “We want you to know that you might be staying at home for a long period of time but you will not be alone.

“We are going to do whatever it takes to support you.”

Sadiq Khan, the mayor of London, the city hit hardest by the outbreak, urged the public to stay home, saying that people will die if social distancing rules are flouted.

He told the BBC’s Andrew Marr Show: “Life has changed, we have got to do things differently for a while now. Social interaction leads to the disease spreading, leads to people dying.

“Don’t leave your home unless you really, really have to.”

Coronavirus fears lead to empty streets and shelves across UK Show all 15 1 /15 Coronavirus fears lead to empty streets and shelves across UK Coronavirus fears lead to empty streets and shelves across UK The usually busy Royal Mile in Edinburgh is empty as people stay away from public areas amid the coronavirus outbreak on 13 March Katielee Arrowsmith/SWNS Coronavirus fears lead to empty streets and shelves across UK Ho bart's Amusement Arcade in Westward Ho!, Devon is offering toilet roll and soap as prizes in grabber machines Rob Braddick/SWNS Coronavirus fears lead to empty streets and shelves across UK An empty platform at Farringdon Station in London the morning after the Prime Minister said that Covid-19 "is the worst public health crisis for a generation" PA Coronavirus fears lead to empty streets and shelves across UK Shopkeepers Asiyah Javed and husband Jawad from Day Today Express, in Stenhousemuir, Falkirk are giving away facemasks, antibacterial hand wash and cleaning wipes to the elderly in a bid to stop the spread of Coronavirus Katielee Arrowsmith/SWNS Coronavirus fears lead to empty streets and shelves across UK A usually busy street in Cambridge is empty as people stay away from public areas amid the coronavirus outbreak on 2 March James Linsell-Clark/SWNS Coronavirus fears lead to empty streets and shelves across UK A hand sanitiser dispenser is seen inside the stadium during the Premier League match between Manchester United and Manchester City at Old Trafford on 8 March Getty Coronavirus fears lead to empty streets and shelves across UK Maaya Indian Kitchen in Milton Keynes is offerig customers a free roll of toilet paper with every takeaway order SWNS Coronavirus fears lead to empty streets and shelves across UK Oliver Cooper[L], was sent home from school for selling spurts of handsanitiser to fellow pupils at 50p a time. He poses with mum Jenny Tompkins by their home in Leeds Ashley Pemberton/SWNS Coronavirus fears lead to empty streets and shelves across UK Empty toilet paper shelves at a supermarket in London on 12 March EPA Coronavirus fears lead to empty streets and shelves across UK A member of the public is swabbed at a drive through Coronavirus testing site set up in a car park in Wolverhampton Getty Coronavirus fears lead to empty streets and shelves across UK A passenger wears a protective face mask as she travels on a bus in the City of London AFP/Getty Coronavirus fears lead to empty streets and shelves across UK A Southampton fan wears a face mask before the match against Newcastle United on 7 March Reuters Coronavirus fears lead to empty streets and shelves across UK A loudspeaker placed in grounds of St Mary's Catholic Church in Broughattin, Dundalk, County Louth ahead of funeral mass later this morning. The loudspeaker has been placed in the grounds after the Catholic Archdiocese said that funerals and weddings should not exceed 100 attendees within the church building PA Coronavirus fears lead to empty streets and shelves across UK A hand sanitising station set up outside Cheltenham Racecourse during day four of the Cheltenham Festival on 13 March PA Coronavirus fears lead to empty streets and shelves across UK People wearing protective face masks walk across London Bridge on 11 March AFP/Getty

Mr Khan urged people to take precautions for their vulnerable relatives “who will die if you don’t” and for the “heroic NHS” staff battling the virus.

Asked if he would close London’s parks, Mr Khan said he would do “whatever it takes” to slow the spread of the virus, adding: “Have no doubt, mixing leads to more people dying.”

Mr Khan also suggested that police could get involved, saying: “Clearly if it is the case that people continue to act in a way that is leading to this disease spreading, then those sorts of things have to be considered.”

Tory former health secretary Jeremy Hunt said social distancing was the only way to give the UK a chance to avoid “the terrible impact on the health system that we saw in Italy”.

He said: “It’s absolutely possible to avoid what we’ve seen, but everyone is very, very worried and the virus is growing very fast and it’s very disappointing when people don’t obey the simple instructions that are being given out.

“It’s not your own life you’re risking necessarily, but you could be risking someone else’s life.”

As the UK death toll rose to 240 on Sunday, vulnerable people, including the over 70s, pregnant women and those with existing health conditions, were urged to stay at home for 12 weeks from Monday.​