The UK government had initially said that the new variant was no more deadly than that which had originally brought life in the UK to a halt.
The 'Kent variant' of the Covid-19 virus, which has spread around the United Kingdom and has been identified in Ireland in recent weeks, could be as much as 30% more deadly than the original strain of the virus in the UK, Boris Johnson said.
Speaking at the UK government's latest Covid-19 press conference, Boris Johnson also revealed that the new virus is between 30% and 70% more transmissible than the old virus.
The higher level of mortality from the new strain, rough estimates of which were offered by the UK's chief scientific officer Patrick Vallance, would lead to between 13 and 14 deaths out of every 1,000 people aged 60 and over who contract it.
The original strain has a death rate of 10 in 1,000 among those aged 60 and above.
The UK Prime Minister said: "In addition to spreading more quickly it also now appears that there is some evidence that the new variant, the variant that was first identified in London and the South East, may be associated with a higher degree of mortality."
Discovered in Kent prior to Christmas, the new variant of the disease has led to the UK entering yet another lockdown, one which many scientists believe should remain in place until May at the earliest if we are to avoid another resurgence of the virus.
In the last week, Covid deaths in the UK have risen by 10%, with today's daily death toll hitting 1,401.
