Finishing times for the Leeds Abbey Dash 2019 will no longer be counted after organisers admitted that the route was 23 metres too short.
The course for the annual Age UK race, now in its 34th year, is supposed to be 10 kilometres from Leeds city centre to Kirkstall Abbey and back.
It was updated this year when the start line was moved to the Headrow and the Cardigan Fields Loop was removed to make the dash 'even faster.'
Following the race, which took place on Sunday, October 27, the updated route was reassessed by officials and the distance found to be short.
Due to the shortfall, times recorded for thousands of runners at the event will no longer be recognised by official boards UK Athletics or the Power of Ten.
On the Age UK website, the charity "apologised" for any disappointment, stating: "The race distance has been re-assessed after the event and due to slight alterations in the course landscape, the race distance was found to be short by 23 metres.
"This is approximately 4 seconds for athletes on a time of 29 minutes for 10k.
"We are extremely sorry that this has happened and apologise for any disappointment this may have caused participants."
Leeds Abbey Dash organisers said that the race will be re-licensed for 2020.
Lydia Curran, Head of Events at Age UK added: "The event is managed and organised with a trusted team which makes every effort to ensure that everyone has a safe and fun day.
"The route was re-licensed for 2020 and in the meantime we are so grateful for everyone who took part and raised vital funds to help improve the lives of older people in Leeds and the rest of the country."
Participants can contact firstname.lastname@example.org or call 0800 1698787 for more information about the error.