It added that the burgers were not initially withdrawn but the board had "reviewed its position in light of more recent media coverage" and began taking frozen burgers from school meals' menus from Wednesday.

BBC: Burgers recalled from NI schools are 'clear of horse DNA'

The sun is a pale smudge in the sky, a pinhole promise of light and warmth, as we lurch and bump across the frozen land in pursuit.

BBC: In Sweden, a long journey home

Concerns about horsemeat in processed beef products first came to light on 15 January and until now recalls by supermarkets have involved frozen products.

BBC: Three held in horsemeat mislabelling investigation

Because the rims of these craters catch rays of light from the sun, this may provide sufficient illumination for the spectrometer to detect frozen water.

ECONOMIST: Astronomy