At Maulvi Fakir's compound, I find a series of tunnels that the TTP and al-Qaeda have carved into the surrounding mountains. It is dark and claustrophobic inside. The entrance is so narrow that I have to remove my backpack just to pass through it. Inside, the tunnels form a labyrinthine web of interlocking bunkers and warrens running deep underground. In places, simply getting through is a gruelling physical experience. Eventually, the tunnels open up to form cavernous rooms capable of holding more than 30 people. This is where al-Qaeda and the TTP's fraternity of the faithful planned terrorist attacks against allied forces in Afghanistan and civilians in Pakistan and the West. 

Going underground: Maulvi Fakir's now abandoned Damadola headquarters still filled with sleeping bags 

The residents here clearly left in a hurry, the mess in their rooms preserved like a terrorist's Marie Celeste. Delicately-patterned Arabian floor cushions are scattered across the floor. Other rooms towards the back are filled with sleeping-bags and paisley eiderdowns. It feels inexplicably homely. These tunnels enabled the guerrilla fighters to move men and munitions undetected. There are two different types here: the first act as trenches providing cover to militants fighting the army. The second are more sophisticated logistical tunnels. Excavated with pickaxes and shovels, they extend up to 20 metres underground and can be hundreds of metres long. The effort poured into constructing them is testament to the TTP's zeal.

Travelling with the army in Bajaur makes it impossible to verify independently what locals think of the fighting and the fighters that imposed themselves on the area. To find out, I travel to Karachi which, unlike Pakistan's other big cities, is host to a vast jumble of different ethnic groups. Almost every family displaced by the war in Fata has relatives there. For that reason, it is home not only to those caught up in the fighting, but also to those who have been doing the fighting. 

Within hours of my arrival in Karachi my fixer calls, "I've arranged a meeting with a member of the Taliban. Do you want to go?" I accept the invitation, assuming, naively perhaps, that this will be a straightforward affair. Just before sunset, we meet a contact outside a textile factory. He hands me the details of another meeting point where I am told to arrive in three hours. For the moment, I am more worried about braving the busy and bustling Karachi rush hour than I am about the meeting. 

By the time I meet the handler at the second meeting point it is dark and late. He asks to drive my car to the final venue. I agree and we set off. Everywhere in Karachi takes longer to reach than it should, but this journey is unusually long. 

Soon we are entering deeply unfamiliar terrain even for locals, my fixer tells me. "Karachi is run by criminal gangs," he whispers. "This is a rough neighbourhood. No one comes here without protection."  The road is potted and uneven, barely more than a dirt track in places, and the car kicks up a trail of sand. There are hardly any working streetlights. The car is squeezed down increasingly cramped and bumpy alleys daubed with sectarian political slogans.