The UK’s terrorism threat level has been upgraded from “substantial” to “severe”.
The move means security chiefs believe that an attack is highly likely but there is no specific intelligence of an imminent incident.
The move follows Monday night’s shooting in Vienna in which four people died, and last week’s knife attack in Nice, France.
Home Secretary Priti Patel said the British people should be “alert but not alarmed”.
Read more: UK terrorism threat level raised to ‘severe’