The House of Commons has voted, the RAF Tornado aircraft are flying from Cyprus, but most people would recognise today that we are somewhere that we would rather not be — at the start of a third armed intervention in Iraq in a generation. However, the situation that has presented itself in Iraq and Syria since June, as a result of the barbaric atrocities and ambitions of Daesh (Islamic State of Iraq and the Levant), has left no option but to take action.

Parliament recognised this on Friday. After the bruising experience of the vote in August 2013, albeit on a related but totally different premise, Prime Minister David Cameron has done the right thing this time in carefully building support for his proposed course of action, including securing proper legal cover and an invitation from the Iraqi government.

Moreover, the UK will be joining a coalition that includes Arab and Muslim states and that is absolutely right. But we have come to this moment very late, and Friday’s vote is just the beginning; it is difficult to see how and when this will all end, and the Secretary of State for Defence’s comment last week that this intervention could take years is both realistic and right.

But it is not just an issue of time scale, it is an issue of intent, determination and open-mindedness. A number of weeks ago, the President of the United States said that the US did not have a strategy which, in the face of Daesh’s onslaught, was worrying. But a strategy has now emerged — at least in part due to the energy of the King of Jordan, whose country sits squarely in the eye of this storm. Any strategy involves the identification first of the strategic objective — in this case the removal of the threat posed by Daesh’s Caliphate ambition.

This removal will entail not just the containment or neutralisation of Daesh, but almost certainly its destruction — at least in the minds of those who would otherwise have chosen to support it, in Iraq, Syria, London or anywhere. With a clearly identified strategic objective, we have also to be open-minded about how to achieve this objective. It may be that joining an air campaign above Iraq will be enough, it may be that providing some support and training to the Iraqi Army and the Kurdish Peshmerga fighters will be sufficient, but if it is not then our schemes of manoeuvre to achieve our objective will have to be reviewed and revised.

There are, however, some awkward facts that we have to face. Daesh recognises no international borders; it wants to impose its Caliphate wherever it chooses. So if our enemy does not recognise borders, but we do, we are constraining our response. Attacking Daesh from the air solely above Iraq is dealing with half a problem not all of it. Of course, operating in Syrian air space is a major challenge — not a legal challenge — but a practical one given the Russian-supplied Syrian integrated air-defence system.

Recognising that is why last month I ventured to suggest that we might have to have some form of dialogue with the regime to enable us to fly over Syria, or if there is no appetite for any conversation with President Bashar Al Assad then air strikes in Syria are likely to have to be confined to the use of unmanned aerial vehicles.

Notwithstanding these practical difficulties, the US has correctly concluded that carrying the fight against Daesh into Syrian air space is right; we may yet come to the same conclusion. If Parliament has to be recalled to make that strategic decision, I hope that that is the last vote for some time, as military operations and tactical decisions cannot be conducted by the occupants of the green or red benches.

The Prime Minister, Defence Secretary and the Chiefs of Staff must act subsequently as they see fit, albeit keeping Parliament informed. Furthermore, it must be accepted that this conflict will ultimately only be settled on the ground — that is the environment on which people live. So, within a proper political framework which addresses the legitimate needs of both the Iraqis and Syrians, Daesh must be defeated on the ground.

There is no appetite to see British or US ground combat units committed to this operation, so for now we must fully support those who are already fighting on the ground such as the Iraqi Army, the Peshmerga and probably the Free Syrian Army, in whom we can now have greater confidence, given that Daesh has broken away.

To do this we may need to provide further intelligence and to send more equipment and training teams to the region and possibly to demonstrate our mutual support to threatened states such as Jordan by deploying units there for exercises or training, if invited. And finally, it has to be accepted that time is not on our side in this conflict.

We have been slow to take action — momentum is still with Daesh. On the diplomatic, political and military fronts, we must catch up, overtake and make it absolutely clear that this kind of barbaric activity has no place in the 21st Century, whether in the name of religion, politics or economic gain. The destruction of Daesh is important, but discrediting the concept of Islamic State is vital. As the Archbishop of Canterbury said in the House of Lords on Friday, we need to offer a competing vision, a more attractive vision. Then, there would be grounds to hope that we can build a safer and more stable future for the people of the Middle East and for sections of our society here at home.

— The Telegraph Group Limited, London 2014