The comment from the PM came after he was questioned during the briefing tonight by a Channel 4 reporter regarding the concern from NHS staff about people who falsely claim the virus is "fake news" and that hospitals are empty.
Responding, Mr Johnson said these people "need to grow up", saying that we have already heard from Sir Simon Stevens, head of NHS England about how much pressure the NHS is under.
The news comes after images of empty hospitals have circulated on social media platforms with individuals claiming that the surge in covid cases across the country is a ‘hoax.’
However, there are more than 30,000 covid patients currently in hospitals around the UK - far more than during the peak of last April.
In Scotland, 1,467 people are in hospital with recently confirmed covid-19, with 100 of these patients in intensive care.
Speaking at the briefing tonight, Mr Johnson said: “The kind of people who stand outside of hospitals and say covid is a hoax and this kind of thing, I really do think they need to grow up.”
Backing Mr Johnson’s debunking of the claims, Sir Simon Stevens, head of NHS England, said this sort of claim is a life threatening ‘lie’ which is ‘an insult’ to frontline workers working hard throughout the pandemic.
Sir Simon said: “It is a lie.
"If you sneak into a hospital in an empty corridor at 9 o clock at night and film that particular corridor and then stick it up on social media and say this proves that hospitals are empty and the whole thing is a hoax, you are not only responsible for potentially changing behaviour that will kill people but it is an insult for the nurse coming home from 12 hours in critical care having worked her guts out under the most demanding and trying of circumstances.
“There is nothing more demoralising than having that kind of nonsense spouted when it is obviously untrue.”