A wildlife expert has expressed his concern over low water levels in a park leaving animals vulnerable to attack, after a swan was killed by a dog last week.

Swan Sanctuary trustee Stephen Knight has criticised the City of London Corporation for leaving the water levels of the Heronry Pond in Wanstead Park low enough for the dog to be able to attack the swan that was killed on Thursday (March 10).

He said: "The City of London has a duty as custodians to look after the environment and the wildlife in the park.

"And those duties do not include altering that environment in a way that leaves wildlife vulnerable.

"This isn't best practice and is costing us an absolute fortune in terms of the money we spend on caring for injured birds."

City of London announced earlier this year that it had deliberately lowered the water levels of the Heronry Pond and Perch Pond to carry out statutory repair works to prevent the growth of an invasive weed called Floating Pennywort.

A park user who lives in Oak Hall Road in Wanstead said: "I've seen dogs in the Heron Pond going after ducks recently, and as a regular park user I think this is unfortunately becoming increasingly common.

"I have been shocked at how out of control some dogs are in the park.

"So I'd like to see more enforcement of the rules as I often see dogs in the water."

The Dangerous Dogs Act 1871 requires all dog owners to keep their animals under control in public places.

Anyone who breaks the law can be fined or have their dog forcibly put down.

The news of the swan's death comes just four years after the same thing happened to a female swan in the park.

City of London, who manages the Grade II-listed park, has said it is ‘gathering evidence’ that it will use to prosecute the owner of a dog that killed the swan last week.

A spokesman said: “We can confirm that a swan has died following an incident with a dog at Wanstead Park.

“We take the death of our wildlife very seriously, and we would urge people to keep their dogs under control and on leads near wildlife to avoid tragic incidents like this from happening.”