BBC:
In the statement, the Metropolitan Police said: “Today’s arrests were made after police received information following initial inquiries by detectives. A decision was made to arrest the five men.
“Following today’s arrests policing arrangements for the papal visit were reviewed and we are satisfied our current policing plan remains appropriate. The itinerary has not changed. There is no change to the UK threat level.”
The current official threat level in the UK is “severe”, which means that security chiefs believe a terror attack is “highly likely”.
The BBC understands that the information acted on by the police was received by Scotland Yard and did not involve intelligence gathered by MI5, the domestic security service.
The Telegraph is clearer about who was arrested: “Pope visit: Five suspected Islamist terrorists arrested over assassination plot.”