The Government is urging people to stay at home this weekend as the weather warms up as it was announced that four NHS staff have died within 24 hours after contracting Covid-19.

Two nurses in their 30s, Areema Nasreen and Aimee O’Rourke, both mothers of three children, have died alongside two healthcare assistants.

England’s chief nursing officer Ruth May said the nurses “were one of my profession” as she urged members of the public not to be tempted to go outside in the forecast sunny weather this weekend.

In the daily Downing Street press conference, Ms May said: “This weekend is going to be very warm and it will be very tempting to go out and enjoy those summer rays.

“But please, I ask you to remember Aimee and Areema.

“Please stay at home for them.”

Ms May expressed her condolences to their families, friends and colleagues and said she feared further nurses will die.

She said: “They were one of us, they were one of my profession, of the NHS family.

“I worry that there’s going to be more and I want to honour them today and recognise their service.”

It comes as the Prime Minister urged the public to stick with social distancing and not be tempted to “hang out” in the warmer weather predicted for this weekend.

Boris Johnson has said he is “feeling better” after suffering from coronavirus but will remain in self-isolation until his temperature drops.

Meanwhile the Department of Health confirmed 684 more people have died in hospital after testing positive for coronavirus, bringing the total deaths in the UK to 3,605 as of 5pm on Thursday.

In a video on social media, Mr Johnson said: “Although I’m feeling better and I’ve done my seven days of isolation, alas I still have one of the symptoms, a minor symptom, I still have a temperature.

“So, in accordance with government advice I must continue my self-isolation until that symptom itself goes.”

Mr Johnson urged people not to break social distancing rules as the weather warms up, even if they were going “a bit stir crazy”.

He said: “I reckon a lot of people will be starting to think that this is all going on for quite a long time and would rather be getting out there, particularly if you’ve got kids in the household, everybody may be getting a bit stir crazy, and there may be just a temptation to get out there, hang out and start to break the regulations.

“I just urge you not to do that. Please, please stick with the guidance now.”

Health Secretary Matt Hancock, speaking at the daily press briefing, said coronavirus “continues its grim march”, adding he “really feels” for those families whose loved ones have died without them by their side.

He reiterated the “instruction” for people to continue to stay at home this weekend, even if the weather proves good.

He said: “We are set for a warm weekend in some parts of the country.

“But the disease is still spreading and we absolutely cannot afford to relax the social distancing measures we have in place.

“We cannot relax our discipline now. If we do, people will die.

“I end with the advice we all know. This advice is not a request – it is an instruction.

“Stay at home, protect lives and then you will be doing your part.”

Asked later if people could go for a picnic for an hour, he said it was “incredibly important people follow the guidelines”, which include people only taking necessary exercise.

He stressed that it was not known when the peak of the virus would come in the UK, although he said earlier he thought it could be in the next few weeks.

He said much work was going on with clinical trials for treatments and said the Government had provisionally ordered 17.5m antibody tests, which can tell people whether they have had the virus and can get back to their normal lives.

“But as I’ve been absolutely clear all along, we will only use them if they work,” he said, adding that no G7 country has found a home antibody test that works.

England’s deputy chief medical officer, Professor Jonathan Van-Tam, told reporters there were no plans to change UK guidance on the public wearing face masks, saying it was not recommended as a way of stopping the spread of Covid-19.

He also said there was no plan to add loss of taste and smell to the list of symptoms people should watch out for if they have Covid-19.

It comes as the first of the Government’s emergency field hospitals to treat coronavirus patients opened in east London’s ExCel centre.

Similar hospitals are in the pipeline across the UK, including in Cardiff, Glasgow, Manchester, Harrogate and Bristol.

The Prince of Wales officially declared the Nightingale open via video link from his Scottish home, saying it “offers us an intensely practical message of hope for those who will need it most at this time of national suffering”.

Meanwhile, the Queen is to address the nation about coronavirus on Sunday.

Earlier, it emerged that two siblings of Ismail Mohamed Abdulwahab, the 13-year-old who died after testing positive for coronavirus, have since developed symptoms.

The development meant Ismail’s mother and six siblings have been forced to self-isolate at their home in Brixton and were unable to attend his funeral on Friday.

He was buried at the Eternal Gardens Muslim burial ground at Kemnal Park Cemetery in Chislehurst by undertakers wearing protective equipment, as a small number of mourners watched from a short distance away.