A KITTEN was sealed inside a plastic box hidden inside a holdall and thrown over a garden fence.

The six to eight-week-old animal had just a few tiny air holes to breathe through and is lucky to be alive, animal welfare inspectors said.

She was very lethargic when she was discovered in Portslade last week, the RSPCA said.

The kitten, who staff named Petra, has since made a good recovery and has already been rehomed, a spokeswoman for the charity said.

But the RSPCA is appealing for anyone who has information about how or why Petra was abandoned to get in touch.

RSPCA inspector Liz Wheeler said: "This poor little thing could have starved to death had this kind man not been looking out of his window when he was and spotted her.

"Not only was she tightly fastened inside the box, but someone had heartlessly gone out of their way to make sure she really had no chance of escape by putting her inside a holdall too.

"She could easily not have been found inside all that packaging.

"We don't know how long she had been like that but it is unlikely she would have survived that much longer.

"As it was, she was incredibly weak and traumatised when she was found, but has since perked up and become a cheeky little character.

"I am not surprised it took someone so little time to fall in love with, and adopt, her."

East Sussex was yesterday announced as the 25th county on a national league table of abandonments, with 456 reports of abandoned animals so far this year, the spokeswoman said.

RSPCA staff and volunteers have seen an alarming increase in animals being abandoned nationally and across the South East.

More than 2,130 animals have been abandoned in Greater London alone since January 1, and 29,770 in England and Wales this year - an increase of 33% since 2009, according to RSPCA figures.

The charity has said it expects the situation to get worse over the winter months.

Contact the RSPCA on 0300 1238 018.