I was shocked on Thursday morning when I dropped my son off for football camp and got chatting to one of the other mothers. On hearing that I had just been in Afghanistan, she asked why we have troops there and suggested they should leave, as they are doing from Iraq.

“But Afghanistan and Iraq are completely different,” I protested. “Afghanistan was a UNbacked intervention. We have reasons to be there. The people want us.”

To many it seems baffling that the prime minister announces we are withdrawing 1,600 troops from Iraq and then it emerges we are sending 1,000 more to Afghanistan. For the British, Afghanistan is now the more dangerous theatre of war. Last year we lost more soldiers in Afghanistan than Iraq — 39 to 29. Two more died last week.

On Thursday evening, after my pitch-side attempt to justify the Afghan deployment, I was speaking in an Intelligence Squared debate at the Royal Geographical Society against the motion “Our mission in Afghanistan is destined to fail: Nato should withdraw”.

Alongside me were Sir Lawrence Freedman, professor of war studies at King’s College London, and Whitney Azoy, director of the American Institute of Afghanistan Studies. On the other side, advocating troop withdrawal, were Major General Charles Vyvyan, former chief of staff at HQ Land Command, the author Michael Griffin, and Clare Short, the former international development secretary who resigned over the war in Iraq.

It was clear that my fellow soccer mom’s attitude was widely held. In the predebate vote, the audience were in favour of withdrawing troops by 240 to 232, with 257 don’t knows.

“We’re repeating the errors we made in Iraq,” insisted Short. “We cannot win in Afghanistan by military force and are just inflaming the situation. Nato could be humiliated and broken in Afghanistan and it needs to get out as rapidly as possible.”

I argued that British and other Nato troop numbers should be increased. Few would now disagree that Iraq was a disaster. But this should motivate us to try to get it right in Afghanistan, which was the real front line of the war on terror. The country was a base for terrorists under a horribly repressive Taliban regime, and it was from there that the 9/11 attacks were planned.

I reported on both the war in Afghanistan and the war in Iraq and saw an enormous difference. Most Iraqis saw the troops as occupiers, but in Afghanistan there was tremendous goodwill. After more than two decades of civil war, most people wanted peace and they saw foreign troops as the only way to achieve that.

The problem is we sent too few too late. Initially the International Security Assistance Force (ISAF) was 4,000 — for a country of 28m people — and they weren’t allowed to go outside Kabul. Kosovo, with less than 2m people, had 40,000 peacekeepers. As recently as 2004, ISAF was still only 6,500 troops. This gave the Taliban confidence to regroup and attack. Nato now has 30,000 troops there, but senior military officers argue this is still not enough.

Last year 4,000 people were killed in Afghanistan, the highest number since 2001. One of the reasons was the overreliance by the Nato command on airpower and its consequent “collateral damage”. But the generals argue that this was precisely because they didn’t have enough troops on the ground.

What quickly emerged as the debate progressed was a clear feeling of the need for a change of strategy. Even on my pro-troop side, none of us was saying that Afghanistan can be resolved militarily. There has to be more focus on a political solution; but I feel “talks with the Taliban” are not possible without some measure of security and threat.

It wasn’t at all clear to me, nor the audience, I think, what Short thought would happen if we did pull out. To do so now would badly damage Nato and soon have the Taliban claiming victory.

All of us talked of the mistakes made by the international community in Afghanistan. There has not been enough focus on rebuilding; we have spent 10 times as much on military operations as on reconstruction.

To my mind we would have been far better off building sewerage systems and power stations (only 6% of Afghans have electricity) than setting up women’s rights groups and holding elections. Just having a parliament doesn’t turn a country into a democracy, particularly when that parliament is full of warlords, who vote themselves an amnesty for war crimes.

When the debate opened up to the floor, there was an obvious thirst for information and a feeling of suspicion that the government is not giving the full picture — a legacy, I suppose, of the way we were misled over Iraq and how Afghanistan was originally presented as a low-risk reconstruction mission.

At the end, the audience voted again. There had been a radical swing: 524 were against withdrawal and just 183 for. Sorry, Ms Short!

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