The Great North Run organisers have had to apologise to 5k runners on Newcastle's Quayside after it emerged their course was too short.
on Saturday morning were later told that they had been sent the wrong way.
The new course meant the runners missed out on 300m - falling short of the expected 5,000m total.
Great Run, which organises the Saturday events, including the Junior and Mini runs, as well as the half-marathon on Sunday, has issued an apology for the error.
They tweeted: "We’ve been made aware that participants in today’s 5k were sent the wrong way on course meaning they missed around 300m of the distance.
"We’re really sorry and we’re looking into what happened. We hope it didn’t take away from your day- we’ll be in touch with all runners directly."
The winner of the men's 5k was James Dunce with a time of 14 minutes and 36 seconds.
In second and third place were Keiran Coleman with 14 minutes, 42 seconds and Josh Fiddaman with 15 minutes and 11 seconds.
The woman's 5k winner was Chloe Wellings who finished at 17 minutes and 5 seconds.
Alex Sneddon was second was 17 minutes, 50 seconds and Hazelle Webster-Costella took third with a time of 18 minutes, 16 seconds.
The Junior, Mini and Wheelchair events are still due to take place on Saturday across the Quayside.
The Great North CityGames take place in Stockton this year however, after moving from their usual home on the Gateshead Quayside.
