Tomorrow in the Commons there will be sorrow. There should also be defiance.

I have worked in and with Afghanistan for many years. I know its people and count many as friends. I have spoken to the injured and the next of kin, whose loved ones gave their lives to protect Afghan interests. I monitored the campaign, week by week, over 12 years and three Ministerial roles.

You do not need to have had those experiences to be appalled at the events this week. There is anger at the effort and sacrifice squandered. There is concern for those left behind and for the horrors to come. These will come at the hands of the Taliban or by the termination of support that will follow. Many will worry for our peace at home, or for the growing pressure on our borders.

We will agonise over the lessons to be learned. If it needed restating, nations need a post-combat plan. To recognise that if you fail to secure women’s rights you fail to secure human rights. That focusing on one country alone, instead of its neighbours too, is wasteful. That fighting for freedom is a mission that will never end. And that takes a long-term plan and investment.

But we feel something else. The scenes on a TV screen about a country far away tell us something about our own. It is something we do not like. Is it impotence, the inability to achieve a different outcome? Is it that we doubt that all human beings should live in freedom? Is it that we can’t bear a nation in decline, because we fear it our own is too? We doubt what we did. We doubt who we are.

Democracy isn’t about deference. It’s about defiance. There are people that say we should feel ashamed. I disagree. I would’ve been more ashamed if we’d never fought for freedom. It made our country safer, at least for a time. It made other countries safer too. It showed that we were prepared to fight for what we believed in. We gave those people a glimpse of a future lit by hope. I am proud of what we did there. Every veteran and their families should know that.

Our confidence and resolve must remain strong.

If you want to see what happens when ‘the West’ stops believing in our values, look at the events of the last few days in Kabul, or for that matter, Syria.

It is not naïve or blind interventionism to say such things. It is when we doubt or abandon those things that define our nation that we fail. How can we be successful if we lose sight of the conditions for it?

Our history has not been one victorious battle after another. We have had losses. We will have losses. But this is a long-term struggle for the potential of mankind.

In this, we will not be defeated.

The Taliban have gained territory. I fully understand what this means for Afghans and for us. It means terror and terrorism. But this is a fight not of just territories, but values and ideas, too.

That is why those who tried to find another way were right to do so. That is why our actions in the coming days and weeks still matter. That is why the courage shown by those UK military and civilians risking their lives to extract Afghans is necessary. Why we must do all we can to help those we fought alongside.

It is why we should not give up hope for Afghanistan.

It is why I will never see this as a fatal blow to us or our aims, nor a victory for the Taliban.

What did they win? Generations of wives and daughters condemned to the stone age? Husbands and sons who have earned the right to suicide? Really, what did they win? Those who support such ideology are doomed.

All of you who have demoralised and corrupted a nation are doomed. You will lose your artists, your historians, your doctors, your poets, your dreamers, your entrepreneurs, your people of action, of protection and of thoughts and letters. You have not won. You have lost everything. You can only build them a wilderness of despair. A prison. A darkness.

Freedom is the light through which the human soul sees. It is the very essence of us. All we hold dear is contingent upon it. We were right to help a nation try to achieve it. We will be right to do so again.

Photo: BBC - British evacuation of Afghan personnel