Pranksters turned an arrow the wrong way directing runners on a 10km run in the opposite direction.
The runners were taking part in a run on Sunday starting at Lancaster Castle and negotiating the cyclepaths towards Caton and back with the Lancaster Race Series when they came across a sign opposite the TA barracks on Caton Road.
Unaware that the sign had been tampered with, some runners ended up running over Skerton Bridge before realising they were going the wrong way and doubling back.
Bill Gardner, race organiser said: “We have a lot of races ranging from 5k to a marathon and we have never really had this sort of problem.They stuck the sign into the ground but facing the wrong way. Luckily we got everybody back safe and they got their t-shirts and medals.People were expecting ro run 6.2miles and they might have been more fatigued.
“Those that did go wrong were trying to beat their target time. A tenth of a mile can make a huge difference. I’m sure people think it’s funny at the time but I’m sure people are not aware of the consequences of their actions.
“We put the sign back correctly as soon as we could and we are offering runners a discount on their next race.
“We have organised 2,000 races and we have only had this one incident.”
On the Lancaster Race Series Facebook page, James Gilleade-Smith said: “I ended up at Black Bear Computers. I had other arrangements and didnt have time to finish after that. Feel gutted after I was doing so well with less than a mile to go. I am fine now, was a bit deflated at the time.”
Alison Wolstenholme said: “Oh no...What a shame for all the runners and so gutting for the organisers. Some horrible folk out there...”
Cathy Titteringtonsaid: “There are some very moronic people around. Gutting for the runners.”