The Great North 5K takes place yearly on the Quayside along the River Tyne, pictured.
CNN  — 

Organizers of the Great North Run, the world’s largest half marathon which takes place from Newcastle to South Shields every September, have apologized after sending runners of an associated 5 kilometer race (3.1 miles) the wrong way.

The Great North 5K follows a route along the Quayside on both sides of Newcastle and Gateshead’s River Tyne. Runners taking part in the race Saturday were accidentally directed around a shorter route, losing about 300 meters (984 feet) of the expected distance.

“We’re really sorry, and we’re looking into what happened,” Great Run, which organizes the Great North 5K, the Great North Run and numerous other events in the UK, posted on Facebook. “We hope it didn’t take take away from your enjoyment of the day and we’ll be in touch with all runners directly.”

Several runners complained on social media that they had been led to believe they’d achieved a personal best time as a result of the shorter course. “I thought I had a PB in the bag,” one commented on Great Run’s Facebook post.

Indeed, winner James Dunce completed the course in 14 minutes and 36 seconds, while 2018’s winner, Callum Elson, finished after 15 minutes and 46 seconds.

Some runners preparing for the Great North Run, however, hoped a similar error would shave some time off Sunday’s half marathon. “Can you knock a few miles off the course tomorrow?” one commented on Facebook.