UK Health Secretary Matt Hancock said a government surveillance study has shown that 17% of the people in London and around 5% or more of the population in the rest of the country have tested positive for COVID-19 antibodies.
Antibody tests tell a person if they have had the virus and have subsequently developed antibodies in response, that might help them to fight COVID-19 in the future, reorts the Metro newspaper.
Addressing a briefing on Thursday, Hancock said the government has signed contracts to supply 10 million antibody tests, with health and care staff, patients and residents prioritised to receive them from next week.
He added that certification systems will be developed for people who test positive for antibodies, so they can be advised on what they can safely do.
While it remains unclear what level of immunity people develop once they have had COVID-19, experts hope a degree of immunity lasts for at least a year or two.
Speaking of the antibody surveillance study, Hancock said: "This was based on a sample but for the public at large to know whether or not they have had coronavirus, we need antibody tests are larger scale.
"The UK government has arranged supplies of these tests on behalf of the devolved administrations and each devolved nation is deciding how to use its test allocation and how testing will be prioritised and managed locally.
"This is an important milestone and it represents further progress in our national testing programme... It's that knowing that you have these antibodies will help us to understand more in the future, if you are at lower risk of catching coronavirus, of dying from coronavirus, and of transmitting coronavirus."
This development comes as the UK has reported a total of 252,246 COVID-19 cases, with 36,124 deaths, the highest number of fatalities in Europe.