A vicious dog ran riot in a farm and began chasing other animals – before eventually killing a newborn lamb.

The pet, whose breed is not known, was taken to Aldenham Country Park, in Dagger Lane, Elstree, by its owner on Saturday morning.

But when it was let off its leash, its owner lost control of the animal and it chased a flock of pregnant ewes around the park for 15 minutes.

Although the incident only resulted in the death of one lamb, park staff fear the stress of the attack could cause a number of still births.

The park is usually a popular spot with families during the holidays - and park manager Olivier Behzadi is keen to ensure the “one off” incident does not deter people from visiting.

He said: “We’ve only had two attacks of this nature, but we have thousands of visitors each week. Everyone is always well behaved.

“We are happy to have dogs on site, but would urge people to make sure they are kept under control.

“Our visitors have nothing to be scared of. We are a happy, safe place.”

Legally, if a dog attacks or chases livestock, the owner of the canine will be held responsible and liable for prosecution.

Police are investigating the incident.