Article published in The Mirror, 12 May 2016. © Richard Kemp

The threat of a terror attack from a rogue IRA group on the British mainland is now a “strong possibility”.

The Mirror revealed yesterday that Northern Ireland-related terror risk was suddenly increased from moderate to substantial, adding to the severe risk posed by Islamic extremists, with an attack by them “highly likely”.

Home Secretary Theresa May said MI5’s decision reflected an ongoing threat from dissident republicans.

This threat level may be with us for some time as it is unlikely MI5 knows the time and place of a planned mainland attack.

But we can be reassured that MI5 is the most capable domestic security service in the world and will work round the clock to try and ensure this never comes off.

The Provisional IRA came to the peace table as the intelligence work of the Royal Ulster Constabulary, the British Army, MI5 and MI6 prevented it from maintaining its terror campaign.

But some hardcore terrorists refused to give up and formed dissident groups.

Last year alone these groups mounted 109 attempted attacks in Northern Ireland.

But a headline-grabbing outrage on the mainland, especially London, is what they seek.

They will not want to squander the efforts and risks needed to launch a successful strike in Britain so are undoubtedly planning one or more strikes.

This new threat and the current menace from Islamic State terrorists means we in Britain now face the highest terrorist threat in our history.