Schools, history societies and individuals who own Second World War gas masks are being warned not to handle them or put them over their faces after tests show that asbestos fibres can be released and pose a health risk.

Members of JUAC (Joint Union Asbestos Committee) have written to the Department of Education to alert all UK schools not to use the old gas masks.

The masks, some of which are now more than 70 years old, contain asbestos.

Tests have shown that if they are worn people are likely to inhale asbestos fibres. The masks, filters and carrying bags can also be contaminated and should not be handled.

JUAC is urging all those who come into contact with the gas masks to follow safety guidelines which include:

• Stop using the masks immediately.

• Contact the local authority for advice on how to safely dispose of the masks, filters and canvas carrying bags.

A spokesperson for JUAC said: "Schools, groups which use these masks in history demonstrations, and members of the public who own these masks do need to be aware of a potential risk to their health.

"It makes sense to stop using them immediately and avoid taking unnecessary risks.

"As handling the masks, their filters and canvas bags may also pose a health risk, we would suggest contacting your local authority for advice before attempting to dispose of the mask or its bag yourself."