A drill to prepare staff for a dangerous animal escaping at Colchester Zoo was carried out today.

All visitors were informed the drill would be happening on Thursday.

In a post online the zoo said: "Visitors have been kindly asked to follow instructions given by staff during this time.

"Please be assured that this is just a drill. This will become one of our quarterly drills which usually takes place prior to the zoo opening.

"On this occasion we have involved visitors to help us to test the procedure.

"This drill was only known to selected management and not by all Zoo staff until now, this will allow them to react as they would in a ‘real life situation’.

"We would like to reassure you that all precautions are taken to prevent incidents which may trigger this procedure with necessary protocols in place to ensure the safety and welfare of our animals and visitors but we are required to participate in drills of the procedure as part of the Zoo Licencing Act.

"Thank you to our visitors for cooperating during the drill and we apologise for any inconvenience caused."

In November 2013 five wolves escaped from their enclosure at Colchester Zoo. One returned unharmed and one was tranquilised, but three were shot.