Apps that direct paedophiles to illegal child porn sharing groups have profited from unwitting adverts from tech giants including Amazon, Microsoft and Dyson.

The apps were available on Google’s play store until they were removed over Christmas by the company after it was alerted to their role in fuelling illegal child porn online.

Some of the apps have been downloaded more than 100,000 times and will still be functioning on the phones of people who purchased them, according to AntiToxin Technologies, an Israel-based child protection organisation that uncovered the trade.

They direct people to groups on WhatsApp, which Facebook owns, where hundreds of paedophiles openly share illegal child porn, most of which is recently produced and largely comprising videos of children, says AntiToxin.