The terrorism threat level in Northern Ireland has been lowered from severe to substantial for the first time in 12 years, Secretary of State Brandon Lewis announced.

The decision to change the threat level is taken by MI5, independent of Government.

The threat level is subject to continuous review, and judgments about the threat are based on a wide range of information.

This is the first time that the threat level in Northern Ireland has been reduced from severe since it was first published in 2010.

Substantial means that a terrorist attack is likely and might well occur without further warning.

Mr Lewis said: “This is the first time the threat level in Northern Ireland has changed since 2010 and shows the significant progress that Northern Ireland has made, and continues to make, towards a more peaceful, more prosperous and safer society.

“It is a testament to the ongoing commitment to protecting the peace process and tackling Northern Ireland-related terrorism, and the tremendous efforts of the Police Service of Northern Ireland and MI5 for their hard won gains over the past decade.

“However, it is not a time for complacency. There is still a minority who wish to cause harm in Northern Ireland.

“As ever, the public should remain vigilant and report any concerns they may have to the police.”

Dissident republican terrorist activity has been at a lower level in Northern Ireland in recent years and security services have secured a number of successes disrupting the activities of the terrorist organisations.

PSNI chief constable Simon Byrne welcomed the reduction in the terrorism threat level, stating that it signalled the successes of police in preventing attacks.

Mr Byrne said: “The independent assessment means the threat has moved from an attack is ‘highly likely’ to ‘likely’.

“This is significant as it signals a success in the long-term efforts made by police officers and staff, our partners, and in particular the community, in achieving the kind of society that we all want and deserve.

“The successes that we have achieved over recent years in preventing attacks, investigating and pursuing groups including the New IRA has brought us to where we are today.”

The chief constable continued: “Unfortunately, there is still a small group of people within our society who are intent on causing harm and dragging Northern Ireland back to the past. We will continue to pursue those individuals and bring them before the courts.

“The public won’t see an immediate change in how we deliver policing and our priority will remain the same: to deliver a visible, accessible and responsive community-focused policing service to keep people safe.”