The coronavirus transmission rate may have fallen, indicating that infections are going to reduce, an expert has said.

Professor Stephen Powis, the medical director of NHS England, said there was early academic evidence that the transmission rate in the community may have fallen below one.

He added that this was important because it meant that people with Covid-19 were no longer passing the virus on to multiple people.

Speaking at the daily Downing Street press conference, Prof Powis explained why this was important.

He said: “We know from evidence around the world, that if there are no social distancing measures in place, one person probably infects on average nearly three people.

“And so if you just work through the maths of that … you very rapidly get into very, very high numbers.

“And so, cutting the frequency which people transmit – so you spread to a fewer number – reduces that from an exponential curve to one that is much more linear.

“And of course, once the transmission rate gets to below one, it starts going in the opposite direction – it starts to drop.

“So that is why we spend a lot of time talking about transmission and avoiding contact, that is the whole purpose of stay-at-home and social distancing, so that that number of people an individual infects on average falls.”

Health Secretary Matt Hancock said there was evidence to suggest the rate of infection was not exponential, but more linear.

He added that the curve needed to flatten before lockdown measures could be relaxed.

Mr Hancock said: “If people want to see the lockdown ended, they know what to do.”