Police square up to tech sector in quarrel over privacy tools.
A Europol chief has warned that encrypted communication is the biggest problem for police in the fight against terrorism.
Rob Wainwright’s comments to the BBC join a growing chorus of officials including prime minister David Cameron in criticising the widening availability of messaging services which cannot easily be deciphered by police and spies.
Speaking to 5 Live Investigates, he said that encrypted communication had "become perhaps the biggest problem for the police and the security service authorities in dealing with the threats from terrorism.
"It’s changed the very nature of counter-terrorist work from one that has been traditionally reliant on having good monitoring capability of communications to one that essentially doesn’t provide that anymore."
Technology companies have started to offer their customers better forms of encryption in the wake of leaks by NSA whistleblower Edward Snowden, which snowed the UK and the US were routinely spying on their citizens with scant legal oversight.
Wainwright attributed this to "a commercial imperative" driven by a perceived demand for privacy, though Silicon Valley has a history of libertarian politics which sets it at odds with government snooping.
A spokesman from TechUK, a lobbying group, also told 5 Live Investigates: "Encryption is an essential component of the modern world and ensures the UK retains its position as one of the world’s leading economies.
"Tech companies take their security responsibilities incredibly seriously, and in the ongoing course of counter-terrorism and other investigations engage with law enforcement and security agencies."
Companies like Facebook have been criticised for allegedly cooperating with US police by handing over customer data, with a case involving the social network having just reached the European Court of Justice, the highest court in the EU.
Many large Silicon Valley now produce annual transparency reports detailing how many requests they receive from various countries, as well as how many they comply with. The US routinely tops these lists, with the UK often appearing in the top five.
Security firms have also started to sell products that leave the keys necessary to decrypt communication in the possession of the customer, meaning the vendor cannot hand over the data to police even if it wanted to.