Blogger Chris Maloney, a member of mountain biking advocacy group Peak District MTB, said: “The worrying thing is we don’t know who it is who’s doing this kind of stuff.
“It’s somebody with a vendetta, someone who has something against we assume mountain bikers or riders – but the things they’re putting out do not discriminate.
“It’s an incredibly dangerous and reckless thing to do.”
Derbyshire Police said no official complaints had been made but said there have been previous incidents were tacks were placed on roads in and around some villages.
“Anyone acting in this manner is putting people at serious risk of injury and, potentially, even death. It is not just cyclists that could be affected – horses and their riders, walkers and other trail users could all be hurt,” the force said.
South Yorkshire Police said it was also aware of reports of alleged trail sabotaging.
Traps have also been found at mountain biking trails elsewhere in the UK, including a plank of wood with 200 nails embedded in it, found in a forest path in Wales.
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. West Midlands Police . Top L-R: Ignacy Brzezinski, Jan Sadowski, Julianna Chodakowicz, Justyna Parczewska. Bottom L-R: Marek Brzezinski, Natalia Zmuda, Wojciech Nowakowski,