Online retail companies should ban the sale of mini mobile phones designed to be smuggled into prisons, said justice secretary David Lidington on Monday.
Often marketed as "Beat the Boss phones", the tiny feature phones can be bought for around £20 to £30 online on sites including Amazon, eBay and Gumtree. On the inside, they can change hands for up to £500.
The phones, which can be as small as lipsticks, are popular with prison inmates due to their discreet size and lack of metal, which allows them to beat metal detectors.
Mobile phones are banned in prisons, in part because they allow inmates to continue criminal activities while they're locked up. But around 20,000 phones and SIM cards were seized by prison guards in 2016, with mini mobiles making up around a third of these.
"It's pretty clear that these miniature phones are being advertised and sold with the purpose of being smuggled," said Lidington in a speech at the thinktank Reform. "I am calling on online retailers and trading websites to take down products that are advertised to evade detection measures in prisons."
eBay banned the sale of the mini mobiles a few months ago, although listings for the phones do still appear on the site. Items that slip through the net are removed manually. A spokeswoman for the retailer did not offer an official comment, but said eBay will be in touch with the justice minister about the issue.
Amazon and Gumtree did not respond to requests for comment.