The standoff between tech firms and intelligence agencies over back door access looks set to intensify after the home secretary revealed that the man who killed killed four people in Westminster this week was using Whatsapp moments before the attack.
Speaking to BBC One's Andrew Marr Show the home secretary, Amber Rudd, said intelligence services must have access to encrypted messaging services to ensure that there is "no place for terrorists to hide".
"We need to make sure our intelligence services have the ability to get into situations like encrypted WhatsApp," said Rudd.
Rudd's comments come after it was revealed that Khalid Masood, who killed four people in Westminster this week, was reportedly on WhatsApp two minutes before he carried out the attack.
Whatsapp, which is owned by Facebook, announced last year that it had installed full encryption to its messaging service, meaning messages are unreadable even if they are intercepted by intelligence agencies or Whatsapp itself.
Facebook has stood firm on its belief that protecting private communications is one of its core principles.
The issue of encryption has resulted in tech companies clashing with governments who believe they should have access to user data for security purposes.