The test could help diagnose tumours sooner, often before any symptoms, scientists hope.
Ministers say the vouchers could be available to families in England as early as Tuesday afternoon.
Why are there more cases of coronavirus in the Aneurin Bevan health board area?
The retail giant is accused of a "disproportionate" campaign to overturn Welsh Ministers' decision.
The number of new daily coronavirus infections is 1,648, down from 3,815 on Sunday.
The often unsanitary conditions in refugee and migrant camps, like this one on Lesbos, pose a challenge for residents trying to avoid coronavirus.
Pubs, hotels, shops and other businesses have been boarded up due to coronavirus closures.
A consultant at the Western General Hospital in Edinburgh says it is currently the quietest he has ever seen.
The BBC’s Gavin Lee took a road trip in Europe's Schengen area to see how free movement has changed.
