Helan Bennett, 43, of Lower Park Road, discovered the bird had been deliberately beaten.

Her husband Patrick said: "My wife went out to water the garden and found a black plastic bag tied to the fence.

"She got a bit of a fright as something started moving inside.

"She untied the bag and found the seagull which had been battered around."

Mr Bennett, who is manager of Southwater Area Community Centre, said one of the gull's eyes was out of its socket and it also had a broken wing.

He said: "It looked very scared as it had been left to die. We did try to feed it a little and give some water to the gull.

"It later had to be put down because of the extent of its injuries."

Mr Bennett called the RSPCA and officers took the gull away.

The grim discovery was made in the afternoon on July 23.

He added: "My wife was completely distressed over this and it has kind of put her off going into the back garden.

"I'm disgusted by this. In as much as seagulls can be annoying, it was a dreadful thing to do to a bird."

A spokesman for the RSPCA said: "We are appealing for information. It looks as if the bird was beaten to death.

"This is not acceptable and is against the law to cause suffering to wildlife.

"People need to learn to live with gulls."

Anyone with information on this incident can contact the RSPCA on 03001234999.