Drain cover fears after 50 thefts in Norfolk
Thieves have stolen 50 drain covers, which will cost £10,000 to replace, from roads across Norfolk.
Drivers, walkers and cyclists are urged to be aware of drains where grating has been removed in south Norfolk and Breckland.
Norfolk County Council described the thefts as "extraordinarily irresponsible".
It believes the grates were stolen for their scrap value. Each costs £200 to replace.
Adrian Gunson, cabinet member for travel and transport, said: "The thefts leave deep open drains that can be a serious hazard to road users, risking damage to vehicles and serious injury to pedestrians, cyclists and motor cyclists.
"Wildlife such as hedgehogs can easily fall in and be trapped."
The cost of replacement is many times the small scrap value of the grates, the council added.
New grates cannot be matched to old frames, so the whole unit has to be replaced.
Grates have been stolen from Spooner Row, Wymondham, Brooke, Alpington, Kirstead, Tibenham, and a number around the A11 in Breckland.
Drain covers have also been stolen in Larling, Croxton, Great Hockham and Stow Bedon.
It is possible that the thieves use yellow jackets to look like council highway workers, the council said.
Anyone who witnesses the removal of grates is asked to take details, including any vehicles being used, and contact police.