Updated: See the latest stories on the coronavirus outbreak.

The NHS may not have enough ventilators to treat all coronavirus patients struggling with the disease, health secretary Matt Hancock has conceded. 

The minister was asked repeatedly by Sky News’ Sophy Ridge on Sunday whether everyone who needed the key piece of equipment would get access to one and could not confirm they would. 

He said prime minister Boris Johnson would be asking British manufacturers to “turn their production and their engineering minds” to making more and additional NHS will be trained to use them. 

The NHS has around 5,000 ventilators and it is thought there could be a shortage. 

Hancock also revealed that the over-70s and other vulnerable people will “soon” be asked to self-isolate for as long as four months to protect themselves from the disease.

He stressed, however, that the government was “not yet” officially ordering such action, but it was “clearly in the action plan” drawn up this week.  

He said: “That is in the action plan, yes, and we will be setting it out with more detail when it is the right time to do so because we absolutely appreciate that it is a very big ask of the elderly and the vulnerable, and it’s for their own self-protection.”

Pressed on when the measure will be introduced, he said: “Certainly in the coming weeks, absolutely.”

The minister also appealed to the public not to panic-buy supplies as shelves across the country empty of essentials. 

Mass gatherings of 500 or more people and school closures are options the government could take, Hancock said, as he said emergency legislation would be brought before the Commons this week. 

It came as the number of deaths in the UK doubled on Saturday, taking the total to 21, while the number of cases hit 1,140 – an increase of 342 from Friday’s figure of 798.

On ventilators, Hancock was asked three times to say whether every coronavirus patient who needed a machine would get one, and he eventually replied: “You’ve heard me say many times that we don’t make guarantees in healthcare and this virus is clearly a huge challenge and we’re learning about it every day.

“So I don’t make guarantees like that. What I will guarantee is we will do everything we possibly can to protect life and to keep people safe.” 

He said there would be a shortage across the world, and added: “The thing that the NHS needs now, more than anything is more ventilator. 

“We’ve been buying as many as we can, but we need to produce more too.” 

He added: “The prime minister is hosting a conference call today to say very clearly to the nation’s manufacturers ventilators are the thing that we are going to need. 

“And frankly, right across the world the demand for them is incredibly high, so it is not possible to produce too many. So anybody who can should turn their production and their engineering minds over to the production of ventilators.” 

Hancock said the bill setting out emergency powers to deal with the coronavirus outbreak will be published on Thursday.

Asked what it will include, Hancock said details would be shared on Tuesday adding he had been working with Labour’s shadow health secretary Jonathan Ashworth. 

He said: “This is a cross-party approach. He’s made some suggestions of other things that should be in there which we’ve included. And it includes a broad range of actions, all about preparing Britain, making sure that we’re ready, should we need to be.”

Hancock said he was “confident” shops will not run out of food but could not guarantee it and warned the government could take further action.

Asked if food supply might be at risk, he added: “No, one of the things we are confident about is that the food supply will continue.”

But pressed to guarantee this would not be the case, he said: “Well we are confident about it. What I can guarantee is we will work with the supermarkets to ensure that people get enough.

“I understand why people might be stocking up but people have got to behave responsibly.

“Supermarkets are right to write the letter calling on people to be responsible and to consider the impact their stocking up might have on others.

“And of course we stand ready to take further measures if that’s necessary.”

Hancock also denied that achieving “herd immunity” was part of the government’s policy in tackling the coronavirus outbreak.

“What we will do is listen to all the credible scientists and we will look at all the evidence,” he added.

“Herd immunity is not our goal or policy, it’s a scientific concept. Our policy is to protect lives and to beat this virus.”

Ashworth, meanwhile, called on Johnson to hold another press conference today and said ministers must do more to explain their approach to the public. 

“The World Health Organisation is saying that we should continue testing and contact tracing. They’re saying that is the best way to break the chain of contagion,” he said.

“The UK have taken a different view that if you feel ill that you just stay at home for seven days and won’t be tested.

“Many people are saying to me that they need a Covid-19 test if they’re ill because they need to know whether they should be interacting with other people in a few weeks’ time.”

He added: “So I just need to understand better why the government is taking a different approach, based on its science, from other countries and I think that’s why it is so important that all the scientific modelling for example is published.”