Several hundred runners who took part in the Norwich Half Marathon in bitingly cold conditions yesterday do not know how long the race took them.
Organisers said an 'equipment malfunction' - linked to weather conditions just before the start of the race - meant several hundred start times had been lost.
They apologised 'unreservedly'.
It means that runners have start times - taken from the moment the first runner crosses the start line - but not chip times - which begin the moment individual runners cross the start line.
Organisers said runners who timed themselves could send in those results.
They added that results would be confirmed this Friday.
Prizes to the first three runners were presented on the day and have not been affected by the malfunction.
Over 2,200 runners took part in yesterday's race.
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