WE have been here before.

New York, Madrid, London, Paris, and now Brussels.

The 21st century has so far been defined by terror attacks by Islamic extremists.

They have repeatedly targeted key cities in the west.

Tuesday’s horrific attacks in Brussels were not the first and will certainly not be the last.

And while attacks in such cities makes headlines worldwide, others do not.

Since November’s attacks in Paris there have been bombings and shootings in Mali, Tunisia, California, Indonesia, Turkey, Burkina Faso, Somalia, and the Ivory Coast.

The attacks may not have been as high-profile as this week’s in Brussels, but hundreds of people lost their lives.

They may not have been terror attacks aimed at the heart of a western city, but they were carried out by the same people.

Call them what you like. Al Qaeda. Islamic State. Isis. Daesh.

I prefer to call them what they are. Cowards and murderers.

They have no religion. They have no nationality. They have no humanity.

They are killers. Criminals, pure and simple.

They will not always be stopped but they will eventually be defeated.

Intelligence has to be used. The law has to be used. And, yes, violence has to be used. Through these measures, the authorities play their part.

The rest of us play our part by standing together.

Unity is the only way to truly defeat terrorism.

Division is precisely what those who killed so many in Brussels on Tuesday want.

They want to see religion set against religion, neighbour against neighbour, country against country.

To succeed, they must divide and conquer.

We must not allow that to happen.

Whatever religion we practice, whatever race we belong to, whatever nation we represent, we must stand together against those whose only desire is to destroy.

We have to be unified by decency and humanity. Good must triumph over evil.

Thankfully, that is what we have seen in the aftermath of Brussels.

People gathering to show their defiance.

People refusing to change their way of life.

People standing as one to let those who wish to deny us freedom, to deny us our very right to life, know they will never win.

What must not be allowed to happen is for extremism to breed extremism.

Again, it is what terrorists want.

There is, of course, more to be done to combat terrorism.

Muslims have to do more to condemn and expose extremists in their midst.

The overwhelming majority of Muslims are as appalled as the rest of us by the murderous acts of those who claim to act in their name.

Rightly or wrongly, there is a perception that Muslim communities do not do enough to combat extremism.

I have no doubt it is happening, but it needs to be more high-profile.

Likewise, the demonisation of Islam by some who wish to use attacks like those in Brussels for their own political ends must not be allowed to go unchallenged.

Such people are also extremists and their policies will do more harm than good.

Above all, we have to continue to celebrate our freedoms and carry on with our everyday lives.

The alternative is to live in fear – and that is the ultimate aim of terrorism.

Terrorists want us to be scared. They want us to be paranoid. They want us to turn on each other.

If we do so then we are finished and they have won.

It must not happen.

Unity and defiance are the strongest weapons we have.

Together we are stronger than cowards and murderers.

We must never forget that.