The police and the NSPCC have issued a warning over the resurgence of an internet craze which sees children deliberately burning themselves in the 'salt and ice challenge'.

Those taking part place a salt and ice mixture onto their skin, resulting in a painful burning sensation they try to withstand for as long as possible. Many suffer second or third degree burns.

The process is often recorded and posted on social media.

West Yorkshire Police Chief Constable Dee Collins posted a warning on Twitter, urging parents to tell their children not to take part in the "dangerous challenge".

The extent of the injuries experienced are so extreme because the skin is numbed with the ice, so participants are unaware of the extent of the damage.

YouTube videos of the challenge date back to 2012 with some amassing more than 6,800,000 views.

The trend swept across the US several years ago however a resurgence is now taking place with British youngsters.

The burns to the skin are similar to frostbite as adding salt to ice or ice water lowers the temperature further than the regular freezing temperature for water.

This is called a eutectic frigorific mixture and can result in temperatures reaching as low as −18 °F (−28 °C).

Children's charity the NSPCC tells ITV News "The rise of social media has contributed to increasing peer pressure amongst children and this 'craze' is another clear example of the risks".

Childline have issued the following advice to children who may be experiencing peer pressure:

If adults are concerned or have any questions on how to approach the subject with their children they can contact the NSPCC Helpline on 0808 800 5000 or visit the NSPCC website.