A warning for all owners to use an appropriate dog lead has been issued in Nottinghamshire after a spate of injuries and deaths.

Haywood Oaks, Blidworth Woods, Sherwood Pines and Thieves Wood are areas where some dog sled users have training permits.

But according to the BBC, three animals have been killed and five injured after playing there. Vets suggested natural poisoning is a likely cause.

Natural England is undertaking tests that have so far yielded no explanation for the incidents.

Vet Jon Ruben, who treated some of the dogs, said they were "severely ill".

And Cheri Fearn of Sutton in Ashfield said Bracken, her terrier, was "howling in pain" before it died. Her puppy is said to be seriously sick.

"We took them to the vets who admitted them straight away and gave them antibiotics and sedatives to calm them down," she explained.

The news is likely to precede a warning usually given to dog owners as the festive season approaches.

Animal healthcare companies often urge people not to feed their pets chocolate, as it can have potentially fatal consequences.