He said: “The herd immunity estimates surprised me.
“However, they are unremarkable when one considers that over 50 percent of adults have been vaccinated, around 42 percent of people have now been exposed to the virus and about 10 percent have pre-existing immunity.
“When factoring in the estimated efficacy of vaccination in terms of sterilising immunity, this – according to the model – means about 70 percent of the population are immune.
“Based upon contact rates at the beginning of the pandemic and estimated transmission risk, this is nearly at the herd immunity threshold.”
Since the week ending March 14, 7.1 million people have received a first dose of vaccine and nearly 100,000 have become infected with coronavirus.
It is believed many others may have caught the virus but had an asymptomatic infection.
One in 10 people are also believed to have acquired innate immunity through previous contact with other coronaviruses.
The study comes after Prime Minister Boris Johnson confirmed Britain would be moving onto the next stage of lockdown.