Any opportunity is gold if you're stuck in prison, so if a phone shaped like a small butt-plug has been launched, the UK government is going to try and ban it.

These tiny phones are typically made in China. They're designed to resemble key fobs of luxury car brands like Bentley, Porsche, BMW and Volkswagen, and they're selling on eBay for about £40 to £60. The phone is touted as the world's smallest mobile phone, but they're reportedly being marketed to prisoners, and the people who supply them.

Authorities caught on, and have found ways to get the phones out of the prisoners hands.. or anuses. A spokesperson told BBC:
"A range of techniques - including body orifice security scanners and high-sensitivity metal detectors - has seen the [overall] number of recorded seizures increase," he said.
Use your imagination.
The demand for these ass-fitting hardware comes from the fact that prisoners were smuggling phones into the prison using their butts. The phones were huge!

[BBC]