BORIS Johnson told the Italian Prime Minister in early March that he wanted herd immunity, according to a TV documentary.

Channel 4’s Dispatches spoke to Italian health minister, Pierpaolo Sileri who said Johnson spoke with Italian PM Giuseppe Conte on March 13.

Sileri told the programme: "I spoke with Conte to tell President Conte that I’d tested positive [for coronavirus]. And he told me that he’d spoken with Boris Johnson and that they’d also talked about the situation in Italy. I remember he said, ‘He told me that he wants herd immunity’.

"I remember that after hanging up, I said to myself that I hope Boris Johnson goes for a lockdown."

"Herd immunity" is aimed at getting a large number of people to contract the virus and therefore develop antibodies to it, limiting the risk of it spreading among the community.

However little is known about the level of immunity gained after catching Covid-19, if any, and the strategy would involve a large number deaths.

READ MORE: WHO questions UK Government's 'herd immunity' theory

In March chief scientific adviser Patrick Vallance said the UK would need about 60% of people to be infected to gain herd immunity and reduce transmission, but ministers have consistently denied this was ever part of their coronavirus response.