British passports are being bought on the “dark web” by terrorists for as little as £750 Europol has warned.
Rob Wainwright, who heads the EU police agency, said the hidden part of the internet was being exploited by terrorists, Mail Online reported.
Mr Wainwright said it had become a “huge underground criminal environment” which was difficult for the security services to monitor.
He was particularly concerned about the trade in stolen passports.
“There is a criminal trading platform … that is substantial,” he said.
“It means criminals and terrorists acquire criminal goods in a more secure way, making it harder … to see what is going on and who is doing it.”
According to research by the Liberal Democrats HM Passport Office’s delivery firm DX has lost 1,291 passports since 2011.
“This shows how criminal gangs and potentially even terrorists are trying to cash in and use other people’s passports,” said Tim Farron, the party leader. “This is a massive national security risk.”
The trade in stolen passports is just the latest manifestation of how the dark web is being exploited.
In October last year, an investigation by BBC South East found that fake train tickets were being sold on the dark web by a self-styled Robin Hood group claiming to be acting on behalf of passengers angered by high rail prices.
Researchers at King’s College, London found that the Tor Browser, designed to mask the identity of people online, was being used for illicit purposes.
They found that 57 per cent of sites designed for the browser were being used to facilitate criminal activity, including drugs, illicit finance, and extreme pornography.