Encrypted messaging services like WhatsApp must make their platforms accessible to intelligence agencies, a top British security official declared Sunday amid reports that the Westminster attacker used the service minutes before his assault on Parliament. Home Secretary Amber Rudd said it is “completely unacceptable” for messaging services to provide end-to-end encryption that means security services cannot listen to plots being discussed. “We need to make sure that organizations like WhatsApp, and there are plenty of others like that, don’t provide a secret place for terrorists to communicate with each other,” she said. Rudd also urged technology companies to do a better job at preventing the publication of material that promotes extremism. British police investigating the attack on Parliament that claimed four victims and wounded dozens say they still believe the assailant acted alone and they have no information indicating that further attacks are planned.