The terrorism threat in the UK has been downgraded to "substantial" from "severe", Priti Patel has said.
The Home Secretary's announcement on Monday means an attack is now deemed "likely" rather than "highly likely".
The decision was announced in a written ministerial statement to Parliament on Monday.
In it, she said: "Despite the change in the threat level, terrorism remains one of the most direct and immediate risks to our national security.
"Substantial continues to indicate a high level of threat; and an attack might well occur without further warning.
"As ever, the public should remain vigilant and report any concerns they may have to the police.
"Government, police and intelligence agencies will continue to work tirelessly to address the threat posed by terrorism in all its forms.
"The threat level is kept under constant review."
The Joint Terrorism Analysis Centre (JTAC) - part of MI5 - makes the decision on the threat level independently of Government ministers, after weighing up intelligence and known terrorist groups. A review is carried out every six months.
The level was raised to "critical" in May 2017 after the Manchester Arena bombing and later downgraded to "severe", where it has remained since September 2017.
Additional reporting by Press Association.
