'We are finding it helpful to check the estimated numbers of people reporting Covid-19 symptoms locally.

The King's College research relies on large numbers of people reporting every day to give reasonably accurate estimates of those who may have Covid-19 and also to learn more about how the disease can spread.

The data is used by university researchers and shared with the NHS. It takes about a minute every day to give a simple report through an app and there are now nearly 4 million people doing so, a huge and valuable public effort.'