If you’d like an idea of what the book is about, here’s an extract from the first chapter. I’d be thrilled to hear what you think.

Zero, Delta, Victor

Kabul, Afghanistan. January 2009

‘Zero Delta. This is Victor one two seven. Whisky. Bishop. Over.’

The man in the passenger seat in front of me in the British Embassy vehicle radios his coded message to the Ops Room. I presume it means, ‘We’re off.’

Then he turns around to look at me. ‘Good morning, Mary. Have you been briefed on movement procedures before at all?’ There’s a Welsh lilt in his voice.

‘Yes. About two times a day since I got here a week ago,’ I tell him.

Nevertheless, he launches into his familiar rapid-fire script.

‘Well, my name is Chris and this here in the driver’s seat is Steve. You’re in a B6 armoured vehicle. The doors will be locked throughout the journey. Please don’t open them or get out of the vehicle unless directed to by Steve or myself.

‘If there’s an incident while we’re moving around the city you should keep your head down and follow our instructions. We’re both armed. The medical pack on the back of the seat in front of you is for self-administration should it be necessary. Do you have any allergies or conditions I should know about? Do you have any questions?’

We’re only going a few blocks through the heavily guarded centre of Kabul to the Ministry of Education. When I first arrived in Afghanistan six years ago, I travelled to work every day in a battered old Corolla with a local driver. Now I have to take a close protection team with me every time.

The car drives away from the back gate of the British Embassy, past armed Ghurkha sentries and half a dozen local guards, through three successive metal boom gates and out into the streets of Kabul.

A block further on, armour or no armour, we are snarled up in Kabul’s perpetual traffic jam. Taxis, minibuses and pickup trucks jostle for right of way at the intersection. At the next corner, Chris flicks down his sun visor. The red diplomatic number plate is attached to the front of it, out of sight unless needed to get past police checkpoints. I expect by now the terrorists have worked out that the diplomats’ cars are the big ones without number plates.

When we arrive at the Ministry another guard lifts another boom gate and we weave around concrete barriers to the main building.

The last time I’d left Kabul I’d told everyone I wouldn’t be coming back. But here I am. Afghanistan seemed to have got its hooks into me.

But so had most of the places where I’d worked during the previous decade. I still pined sometimes for the muddy chaos of post-war Kosovo, the sub-zero temperatures and bargain-priced opera tickets in Kiev, and the crowds and noise and traffic of Manila. These places were all very different from each other, but in other ways, they were much the same in their poverty, dysfunction and insecurity.

They were also a million miles away from the comfortable life and predictable government job I’d had before I’d accepted a six-week consulting assignment all those years ago. Since then, I’d lived in a dozen different countries, most of which I’d known nothing about before I’d arrived, started learning and promptly forgotten half a dozen languages, survived without reliable electricity or even a regular water supply, and been a bystander as history unfolded in some of the most desperately troubled places in the world.

I’d been delivering international aid to those countries, but I wasn’t the kind of aid worker who looks after starving children or puts up tents for refugees. The help I bring is in the form of red tape and regulation, taxation and accounting, spreadsheets and computers.

My job is to tell governments how to raise more taxes, spend them wisely and ensure the money isn’t stolen by corrupt officials, or by the very politicians I’m giving advice to. Not surprisingly, officials and politicians are not always keen to accept the changes my colleagues and I recommend. On the other hand, some of our recommendations have not always been sensible or implementable.

Chris follows me up the stairs and along the dusty Ministry of Education corridors. He’s a stocky guy wearing an armoured vest under his short-sleeved shirt. He looks like Arnold Schwarzenegger with a hump. There’s a curly wire coming out of one ear and a microphone pinned to the front of his shirt.

He sits outside in the corridor throughout my long and rambling two-hour meeting about the Afghan education budget. When I’m finally ready to go he leans forward and talks to his well-developed left pectoral muscle. ‘Stand by. Stand by.’

Steve has the vehicle waiting outside the door by the time we get downstairs. At the exit gate he turns right. I could have told him it would be better to turn left. I’ve been here so many times before. But they’re supposed to be the experts. They’re supposed to be protecting me.

So now we are inextricably tangled in Kabul’s afternoon rush hour. It’s 3.30 pm, knockoff time for the city’s civil servants, and the main streets are clogged with vintage buses taking them home. There’s no alternative now but to follow them in a huge loop of one-way streets through the heart of Kabul, past the new mosque shimmering in the winter sunlight, around Zarnegar Park and in front of the fortified five-star Serena Hotel, just to end up almost where we started.

Steve drives aggressively. He tries to push his way through the traffic, but there’s not much that pumping the clutch and spinning the steering wheel and jerking the brake pedal can do about the everyday chaos of Kabul’s city streets. We are hemmed in by Afghans on bicycles, pedestrians crossing the street without looking, handcarts of fruit for sale pushing against the traffic flow, beggars looking sadly through the tinted windows and half a dozen other B6 armoured vehicles driven by aggressive close protection teams also heading in the same direction as us, towards the diplomatic safety zone.

It would definitely have been easier if we’d turned left.

Finally, we arrive at the Embassy compound, drive back through the three boom gates, and wait while the guards check under the chassis for hidden bombs.

‘Zero delta. Victor one two seven. Bishop. Lincoln. Over.’

I guess that means we’re home.