Image caption One of the fidget spinners tested by the BBC's Watchdog programme

Fidget spinners that can puncture the skin have been discovered for sale in the UK by a BBC Watchdog investigation.

Safety fears have been raised about the spinners - a craze that has fascinated children and frustrated parents - with others found to fail safety tests.

Some in the shape of a "shuriken", an offensive weapon in the UK, were found to be on sale on eBay.

Tests found they could damage eyes and puncture skin. The auction site said they would be removed from sale.

The spinners, originally designed to help children with conditions such as autism deal with stress, have become a playground craze.

The Watchdog team bought three fidget spinners - marketed as toys for children - from eBay.

They had the appearance of a "death star" or "shuriken". The items were put through testing by blades expert Professor Sarah Hainsworth. She tested the spinners by stabbing into a tomato, used as a substitute for an eye, and pork skin, used as a substitute for human skin.

All three spinners had the ability to puncture the tomato, and two out of three were able to puncture the pork skin.

A spokesman for eBay said: "These items are absolutely not permitted and will be immediately removed. We'd like to thank the programme for bringing these items to our attention."

BBC Watchdog also bought five fidget spinners from local shops. A toy safety expert concluded that none of them should have been sold as they did not pass essential toy safety tests.

Concerned parents have also recounted evidence of poor quality spinners, including one who found a large shard of metal protruding from the toy.

Image copyright Reuters

Advice from Trading Standards for anyone buying spinners and other toys includes:

Always look for the CE mark on packaging, showing it meets European safety standards, according to the manufacturer. If you can't see one - don't buy it

Always buy from a reputable seller, and do not buy these toys for children aged under three as they have small parts that could present a choke hazard to children

You can watch the full story on BBC One at 20:00 BST on Wednesday 2 August, and later on the BBC iPlayer