The government has hired 25,000 dedicated staff and aims to be able to trace the contacts of 10,000 people a day, which it said could be scaled up if needed.
Anyone who tests positive will be asked for details - either by a contact tracer or by a text or email - of people they have been in close contact with over the last seven days.
"That enables us then to take action in that place which will be restrictive on the individuals who live and work there. but as a result of that we'll be able to provide greater freedom to millions of other people across the country, enabling us to continue to ease the lockdown, ease the return to school, to work and to the daily activities that we all want to get back to", he told the BBC.
It has also been ramping up the country's testing capability to 200,000 tests a day, through the establishment of 50 drive-through sites, more than 100 mobile testing units and three mega laboratories.
Chairing Wednesday's Downing Street daily briefing, Hancock said until an effective treatment or vaccine comes through, the test and trace program is a big part of how the country moves forward out of lockdown. First, through testing we hunt down the virus finding out who is infected right now and I use "we" very deliberately because we all have our part to play.
Britain has Europe's highest death toll from the pandemic, with more than 46,000 fatalities attributed to the virus by mid-May, according to official statistics.
Each local authority will be given funding to develop "tailored outbreak control plans", led by council leaders and directors of public health, working with NHS trusts and other partners. "If you get a call from an NHS (National Health Service) contact tracer, you must isolate", said Hancock.
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The 2020 WNBA Draft presented by State Farm will be held on Friday April 17 as a virtual event without players, guests, or media. Throughout her career, she's been one of the most consistent post players throughout women's basketball.