The fact that Britain is now deemed to be at an increased level of threat from dissident republicans has come as a surprise but is nevertheless a serious and alarming development.
Home secretary Theresa May announced yesterday that MI5 had raised the threat level from moderate to substantial, which means that it is believed a terror attack is a `strong possibility'.
Little information about any possible threat has been forthcoming or what the likely target might be but we can presume that the security services have received intelligence indicating that some form of dissident attack is planned in the near future.
Mrs May said the government was working with the police and other agencies to ``ensure appropriate security measures are in place'' although it is not clear what form this will take.
However, any potential increase in the dissident campaign of violence has to be viewed with considerable concern.
It is just two months since a group known as the `IRA' planted a bomb under prison officer Adrian Ismay's van in east Belfast, causing injuries that led to his death.
This dreadful murder underlined the lethal danger posed by this and other dissident groups who continue to target police and prison officers, carrying out reckless bomb and gun attacks and putting the lives of security forces and civilians at risk.
Consequently, the threat level in Northern Ireland remains unchanged and is assessed as severe.
It is worrying that despite obvious successes by police on both sides of the border, the dissidents are persisting with their brutal and ultimately futile campaign.
What support they do have is minimal and they are deluding themselves if they think that taking a life or a number of lives will bring about a united Ireland.
If they have a coherent strategy they should put it before the electorate and see what mandate they receive.
In the meantime, people in Britain and Ireland, north and south, must be vigilant in the face of this unconscionable threat and report any suspicious activity to the police.
