Good Morning Britain's Dr Hilary Jones slammed those flouting coronavirus lockdown rules in a fiery rant.
The show's resident doctor said those "finding excuses to get around the guidelines" have "blood on their hands".
Speaking to presenters Ben Shephard and Kate Garraway, Hilary said: "We have to be realistic.
"We have got better treatments, and some good news, we have vaccination rollouts, we have got lockdown and we have got new medications and airport testing, all of which could be better but we are getting there slowly.
"But we must take lockdown much more seriously because when I look on the road, there are more cars than saw in the first lockdown.
"People are finding excuses to get around the guidelines, and they have got blood on their hands because we are in a very serious situation."
Ben added that 10,000 people had been admitted to hospital with coronavirus since Christmas Day, with 800 new admissions daily.
Dr Hilary said that by the end of this month, hospitals could be up to 5,000 beds short.
He continued: "I don’t want to scare people, I just want to instil a sense of reality about where we are."
"This is not the time to be complacent, and virus deniers and flouters have blood on their hands," he explained.
Later in the ITV show, Kate Garraway branded Stanley Johnson "naughty" as she called him out for travelling by tube without a mask last year.
Boris Johnson's father, 80, was filmed appearing to breach restrictions as he got on a London tube train without wearing a face-covering in December 2020.
Kate asked Stanley about the tube incident as she said: "Have you been wearing a mask?
"Because you were pictured not wearing one even in December on the underground."
"You are naughty!", she added.
Stanley defended himself as he remarked that "sometimes the mask slips".
He explained: "Sometimes the mask slips, as you know, by accident."
Good Morning Britain airs weekdays at 6am on ITV.