Eilish McColgan's 10,000m record set in Glasgow during the Great Scottish Run has been invalidated after the course was found to be 150m short.
The 31-year-old Commonwealth Games champion set a new British record and surpassed her own European mark by finishing in 30 minutes and 18 seconds on October 2.
But an error mean the course was not laid out in line with the agreed plans.
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The Great Run Company, which organises the race in Glasgow, has apologised to McColgan.
Paul Foster, chief executive of the Great Run Company, said: "We were recently made aware of a discrepancy with the 10k course at this year's Great Scottish Run. Following an internal investigation, we have established it was 150m short.
"The shortfall in the distance was wholly due to human error. An area of the course was not laid out in line with the previously agreed plans.
"This error had a marginal knock-on to the half-marathon, but it was within tolerance and the course on the day was valid.
"We're extremely disappointed that this happened at the 10K, on what was an incredibly positive return to the city for the Great Scottish Run following the pandemic. We will be reviewing our internal processes to ensure we cannot make this mistake again.
"We know we've let our customers down on this occasion. There are no excuses for this happening and we're very sorry."
This was the second time the Great Scottish Run has fallen short after the half-marathon in 2016 was found to be roughly 150m too short.
The mistake invalidated the record set by Callum Hawkins, who won the half-marathon in 1:03:35 that year.
The Great Run Company say the error had a marginal effect on the half-marathon but it was within tolerance and the course was valid.
The records for McColgan had capped a stand-out year for the Dundonian after her first major title in the Commonwealth Games 10,000m, a silver in the 5,000m in Birmingham, plus two medals in the European Championships.
McColgan, who shaved one second off her previous best in the race in Glasgow, had not run outdoors in Scotland since the 2014 Commonwealth Games, but competed in the Great Scottish Run after withdrawing from the London Marathon.