COVID-19: Do face masks work? Here is what scientific studies say

Wearing a face mask is soon set to become a personal choice rather than something required of people inside buildings and on public transport. Although the government has repeatedly stressed that it would be guided by the science, a rift in approach is showing between groups such as the British Medical Association and health minister Helen Whately. So - what do peer-reviewed scientific studies say when it comes to how effective face masks are?