Charity cyclists suffered punctures and could have been seriously injured after a saboteur scattered drawing pins on the road.
Around 50 riders taking part in the Marlow Red Kite charity bike ride were forced off the road after drawing pins were discovered to have been placed across the route near the villages of Oakley and Brill.
Luckily, organisers were able to remove handfuls of drawing pins from the route before the majority of the field arrived.
Event director Steve Tolmie said: “Its incredibly disappointing that a narrow-minded individual has attempted to spoil the day for a large group of people.
“It could have been considerably worse because a cyclist could have received a serious injury as a result of this attempt.
“We reported this to Thames Valley Police immediately and they take incidents like this very seriously.
“Safety to our riders and other road users is our number one concern and we would be very keen for anyone who saw anything suspicious on the B4011 near Oakley to contact police with any information.”
Media officer for the Marlow Red Kite Ride Jamie Baker added: “I was based at the first feeding station in Brill and I became aware that a lot of cyclists were stopping because of punctures.
“The lads were not happy having to change wheels and we got a broom to sweep up a pile that we found near to the village.
“There were about 50 punctures, although we cleared up the pins before the rest of the field came through.
“Some people did ride with pins in their tyres.
“It is the fourth year we have held the race but the first time we have had anything like this.”
Mr Baker said he had experienced similar sabotage attempts in the past.
He said: “When I was taking part in a ride in Scotland lots of carpet tacks were put on the road going up a climb.
“There were hundreds of punctures and people had to carry their bikes.
“It turned out that it was the chairman of the local parish council who did it and he was ostracised by the community for what he had done.
“I can understand the frustration of people and they don’t like us coming through but you will not stop cyclists.
“There are procedures but this is not the way to do it.
“It could have been much more serious if a cyclist had say fallen off into the path of an oncoming car.”
It is hoped that this year’s event will raise more than £7,000 for charity.