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

In a video on social media, 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.

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.

Speaking about his own health, 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.”

The Department of Health said as of 9am on Friday, a total of 173,784 people have been tested for coronavirus, of which 38,168 tested positive.

Public Health England said 11,764 tests were carried out on Thursday in England.

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

The temporary NHS Nightingale Hospital is able to take up to 4,000 patients and will be staffed by NHS medics with help from the military.

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

The Prince of Wales officially declared the Nightingale open via video link from his Scottish castle, 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, Health Secretary Matt Hancock described having coronavirus as a “pretty unpleasant experience” as he promised further action on testing.

He said he has now fully recovered from the “nasty” illness, which saw him suffer sleepless nights and an “incredibly” sore throat, as well as losing half a stone.

“It was a pretty unpleasant experience, I went downhill on Thursday last week and for a couple of nights it was very hard to sleep, incredibly painful throat, it was like having glass in my throat,” he said.

Meanwhile, two siblings of Ismail Mohamed Abdulwahab, the 13-year-old who died after testing positive for coronavirus, have since developed symptoms, according to a family friend.

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 on from a short distance away.

In Walsall, nurse Areema Nasreen, who was in intensive care on a ventilator after testing positive for the virus, has died.

The 36-year-old mother of three had been on a ventilator at Walsall Manor Hospital where she worked as a staff nurse on the acute medical unit.

Walsall Healthcare NHS Trust’s chief executive Richard Beeken said they had hoped to take Ms Nasreen off the ventilator as she had started to show signs of improvement but she then deteriorated.

Responding to the news, Mr Hancock told the PA news agency: “I pay tribute to the NHS staff who’ve died serving the NHS, serving the nation.”

In a statement, Mr Beeken said Ms Nasreen had died in the early hours of Friday morning.

“Any death is devastating but losing one of our own is beyond words,” he added.

East Kent Hospitals University NHS Foundation Trust also paid tribute to staff nurse Aimee O’Rourke, another mother-of-three, who died aged 39 on Thursday after contracting Covid-19.

In a Facebook tribute, her daughter, Megan Murphy, said: “Look at all the lives you looked after and all the families you comforted when patients passed away.

“You are an angel and you will wear your NHS crown forevermore because you earned that crown the very first day you started.”

Elsewhere, the husband of TV presenter Kate Garraway is in intensive care battling coronavirus.

Derek Draper is receiving emergency hospital treatment and Garraway was forced to self-isolate after she showed symptoms of the virus.

Speaking on BBC Radio 4’s Today programme earlier, Mr Hancock said it is unclear whether he is now immune to Covid-19.

“I took advice on that and the advice is it’s highly likely that I am now immune, or have a very high level of immunity,” he said. “But it’s not certain.”

He said there was a “stream of work under way” looking at immunity and the possibility of immunity certificates so those who have had Covid-19 can get back to normal.

Mr Hancock said the virus is expected to peak in the UK in the next few weeks, adding: “It’s very, very sensitive to how many people follow the social distancing guidelines.”

On Thursday, the Cabinet minister pledged England would hit 100,000 tests per day by the end of the month following widespread criticism of the Government’s testing strategy.

The UK already has antigen tests, which tell people whether they currently have Covid-19, and work is ongoing to validate antibody tests to see whether people have previously had the infection.