Computer systems were not functioning but data was manually adjusted, artillery expert Steven Krstic said.

BBC: Data error 'caused death of Kent Sapper Mark Smith'

"Unfortunately, having 1, 640ft (500m) from troops or villages is just an ideal circumstance, " Mr Krstic said.

BBC: Data error 'caused death of Kent Sapper Mark Smith'

Mr Krstic said because the computer forecast system was down, gunners could have used the manual adjustments collected through the day, but they used weather data from early that morning.

BBC: Data error 'caused death of Kent Sapper Mark Smith'