Tiny mobile phones are being smuggled into jails INSIDE visitors.

The Zanco Bee is marketed as the world’s smallest phone and is sold on the web for less than £25.

But sources claim they fetch up to £800 on the inside.

One Facebook user says the devices – banned behind bars – can be hidden in body cavities.

Sellers advertise them as 100 per cent plastic, suggesting they can’t be picked up by scanners.

Prison officers seized 3,000 mobiles from inmates in England and Wales over three months last year (
Image:
PA)

A source said: “Prison officers are facing ever increasing pressure to keep control inside jails and they’re powerless to stop these phones from slipping through the net.

"It’s terrifying that prisoners on the inside have access to these devices so they can continue to carry out criminal activities.”

Prison officers seized 3,000 ­mobiles from inmates in England and Wales over three months last year.

One customer wrote on Amazon that a rival phone was “very small and easy/painless to hide”.

But he was concerned that the model wasn’t 100 per cent plastic, so wouldn’t necessarily beat the BOSS – body orifice ­security scanners.

Last year a documentary ­revealed mobiles had been smuggled to prisoners hidden inside Mars Bars. Channel 4’s The Secret Life of Prisons also detailed how drugs are flown in by drones, concealed in trainers or sprayed on to children’s drawings.

This month our sister paper the Sunday Mirror revealed a series of shocking images that shamed our failing jails. A swaggering lag and his mates were pictured with a hoard of banned booze, drugs, and a Nando’s takeaway.