Just 662 sales separate the Lewisham and Greenwich NHS Choir's A Bridge Over You from Justin Bieber's Love Yourself, according to the Official Charts website.
The NHS Choir 'closed the gap overnight', the website reports, and could yet get over the line to become the Christmas number one.
NHS Choir
The choir has pledged to donate all proceeds from sales of its hit single to health charities.
Following a string of appearances on radio and television, the group has been urging supporters to buy its single to help them earn the Christmas crown.
662 combined sales behind Justin Bieber. Pls download and stream. We are so close! @NHS4XmasNo1 @LoveYourNHS https://t.co/eYHdJQfx4w
— LG NHS Choir (@Choir_NHS) December 23, 2015
