THE IRA once infamously stated that they “only had to be lucky once”.
For any group of terrorists that is regrettably true.
Today, sadly, the threat of an atrocity in the UK has remained at ‘severe’ for more than two years.
The fact nothing’s happened is thanks to the vigilance and dedication of our police and security services.
We, too, must play our part.
Our most senior counter-terrorism officer is appealing to all of us to report any suspicious behaviour.
Assistant Commissioner Mark Rowley says that a staggering 13 plots have been thwarted since the murder of Lee Rigby in 2013.
Several were on the scale of the attacks in Brussels and Paris.
Not all of them were attributable to Isis and Al Qaeda; the far right and others are active too.
However, of the 850 Britons thought to have joined ISIS, half may have returned to the UK.
Radicalised and battle-hardened, they are the biggest concern.
Of course MI5 is doing all it can, but it takes 36 officers to follow one suspect continuously and, with 500 ‘live’ investigations at any one time, the scale of the task is alarming.
The timing of a chilling, recent drama documentary on BBC2 on just how difficult it is to stop a determined attacker is pertinent.
It doesn’t make it any easier for those trying to keep us safe that the proportion of terrorists known to MI5 has plunged from 61 per cent to 29 per cent since 2011.
To defeat terrorism, we need to understand it.
A comprehensive, new study into Islamist terrorism by the Henry Jackson Society focuses on the 269 individual convictions and suicide bombings, and 400 offences, recorded in the UK since 1998.
It’s no surprise that extremism is strongly linked to highly segregated areas.
Better integration is the key.