An industrial estate may not be the most idyllic location to rear one's young but for two swans it is home.

Huddled amid plastic bags, wooden pallets, shopping trolleys and bricks, the breeding pair are doing their best to ensure their clutch of eggs hatches safely.

But now their nest has come under attack from a greater threat.

Gangs of youths have spotted the birds and subjected them to a series of attacks.

Three of the eggs have been smashed and the regal pair have even had rocks thrown at them.

Bird lovers have set up a round-the-clock watch.

Chris Niall, an officer for Worthing and District Animal Rescue (Wadars), said the nesting ground, in the Willowbrook Trading Estate in Worthing, had become a "playground for hooligans."

He said the behaviour was inexcusable and the site needed to be cleared up.

He said: "The whole area is an absolute disgrace. Both swans are unharmed but they are very territorial and will remain on the nest whatever happens, which makes them sitting targets."

The male swan stays close to the nesting female to protect her but the youths are even using catapults from the safety of the banks.

Mr Niall said: "How they can get any enjoyment from it, I do not know. What they are doing is completely inexcusable and, if they are caught, they will be prosecuted."

He said local companies were keeping an eye on the swans but their help was limited to business hours.

Mr Niall said: "To relocate the swans we would have to catch them both, then the young would definitely not hatch.

"If we release them in another area, they will fly straight back there within a couple of days."

Staff at Dinnages Body Shop in Willowbrook Road are appalled by the abuse and continually rush from work to stop the gang.

Wendy Legg, who works in Dinnages, said people regularly dumped rubbish, cars and mattresses by the stream and some of the debris was used against the swans.

An Environment Agency spokeswoman said action was being taken to keep litter down.

She said: "If we find evidence in any fly-tipping, which we do regularly, we take people to court."