I had been trying to get to Aleppo for ages, but was unable to do so because rebel activity had cut off the city from the outside world. Syrian government military successes at the start of January meant there was at last a safe road. I hired a driver, was allocated a government minder (very handy at checkpoints), and booked into a hotel. Driving north from Damascus, we picked up a 22-year-old Syrian army lieutenant called Ali, returning to his unit after eight days’ leave with his family.

We drove through Homs — miles and miles of utter devastation — and then east on to the Raqqa road. Ali told me that he had been assigned to Kuweires military airport east of Aleppo, which was under siege for three years from Al Nusra and Islamic State forces. He spoke of daily firefights against Isis fighters. For long periods his unit was entirely cut off. When Ali was shot in the chest there was no question of being airlifted out. He convalesced in a field hospital. Eventually the siege was lifted and Ali could return home and see his parents for the first time in more than two years. ‘The secret behind Kuweires was the loyalty of the soldiers. We had no tanks. I lost 82 comrades,’ said Ali. Now his unit is mopping up Islamic State positions round Al-Bab to the East of Aleppo.

When we reached Aleppo there had been no electricity for 112 days and no water for almost two weeks. Improvised mortars — gas canisters explosive enough to bring down buildings — can fall anywhere. Seventeen of the giant student dormitory blocks at the university are now set aside for displaced families from rebel-held areas. All the families have terrifying stories to tell about intimidation and murder at the hands of fanatical Al Nusra, Isis or Free Syrian army forces. These refugees are everywhere. I knocked on the door of Baron’s Hotel, the famous establishment in downtown Aleppo where Agatha Christie wrote Murder on the Orient Express. There I learnt the sad news that the charismatic owner, Armen Mazloumian, had died of a heart attack the previous week. His widow Rubina told me that he had refused to close down his hotel when the crisis began, opening his doors instead to victims of jihadi terror from the countryside.

Aleppo’s favourite film this winter is Bridge of Spies, Steven Spielberg’s masterpiece about Cold War espionage. It is a movie that Aleppans vividly understand. They live in a place where survival means crossing enemy lines to negotiate deals about water, electricity, hostages. Aleppo has characters whose lives are even more heroic than James Donovan, the lawyer played by Tom Hanks who crossed into East Berlin to negotiate the release of Gary Powers. At the education ministry I met a schoolmistress who had just made a five-day journey through endless Islamic State checkpoints to collect her pay cheque. She was about to return home, fully conscious of what lay ahead. Syrian Army troops are advancing on her town. ‘Islamic State will turn us into human shields,’ she told me.

My time in Aleppo coincided with the turning point in the Syrian civil war. Assad’s forces, with the help of Russian air power, cut off the line of supply from the Turkish border to the jihadist forces encircling the government-held areas of the city. Deprived of fresh fighters, guns and ammunition from their Turkish sponsors, Al Nusra and other groups encircling the city are, over the long term, doomed. Islamic State, which sells its oil through Turkey, will start to run short of money. Think of Stalingrad in 1942: the besiegers are now the besieged.

When I returned to London I read in the newspapers that this turn of events was regarded as a calamity. Of course, it does depend on your point of view. Government-held Aleppo was under siege from jihadi forces until late last year. That was never reported. Now the areas of Aleppo held by the rebels are coming under siege. That is reported in the western press as a catastrophe, and has brought a concerned response from the British Foreign Secretary.

Again and again I was asked: why is Britain supporting the terrorists? Western media rightly emphasise Assad’s atrocities. But the Aleppans I spoke to regularly pointed out that under Assad’s regime women can walk alone down the street and pursue a career; that a broadly liberal curriculum is taught in the schools; that Christians can worship at their churches and Muslims in their mosques. These Aleppans have lived under siege from groups hellbent on the imposition of a mutant version of Wahhabi Islam. They know that many of their fighters are foreigners whose ambition, encouraged by Turkish and Saudi sponsors, is to extinguish Aleppo’s tolerant culture and drive every last Christian out of the city. These Aleppans have a point. When the history of the Syrian civil war is finally written, historians will indeed have to confront the question: why has it been British government policy to turn the ancient city of Aleppo into present-day Kandahar?

Peter Oborne is political columnist for the Daily Mail, and an associate editor of The Spectator.