The primates have a distinctive call

Trinity parishioners and visitors to the zoo are being asked to help look for the silver-coloured marmosets, which have roamed outside its fences.

Normally, the marmosets are allowed to wonder freely around the grounds of the zoo.

But this time the primates have strayed too far and their keepers are concerned for their welfare and keen to find them quickly.

The marmosets are described as squirrel-like creatures with silvery fur, a black tail and a pink face.

They have a very distinctive high-pitched call.

Their absence was discovered on Monday morning when keepers went to feed them.

Anyone who sees them is asked to call the zoo.