On Wednesday Joanna was driving us along the Military Road, the Autumn sunshine making shadows across the fields towards Hadrian's Wall. We were listening to the news about King Abdullah's visit to London when I remembered a journey I'd made nearly thirty years ago on another dead straight road beside an icon of political power, the oil pipeline in Saudi Arabia.
A beautiful girl had seduced me into giving up my job, house and car. We bought an old Volkswagen combi van, added a cooker and a bed, and set out to drive to India.
In 1979, with my moustache and long hair I looked a bit like Robert Plant, and she'd floored me with her flowery hippy dresses and determination to meet the Dalai Lama.
Disaster struck as we camped in the car park of the Topkapi palace in Istanbul. The BBC announced the overthrow of the Shah of Iran. We studied the map. Iran was now blocked as there was only one way through: South, through Syria and Jordan, and then along a straight line through the desert marked Saudi Arabia.
A couple of weeks later, we drove into the compound of the Saudi Embassy in Amman. There were about fifty other camper vans, all painted in bright hippy colours, and standing outside were about a hundred weeping Australians. It wasn't the rugby season: they'd been denied visas and now had to face the long drive back to the UK. Resigned to failure, Jilly made a cup of tea in the van and I took our passports up to the visa window.
The man behind the glass frowned, stared at both passports, then slowly softened.
"Geel-an. Your sister?" he asked.
For a moment I looked blankly. Then, just as I opened my mouth to correct it dawned on me. My middle name is Gillan. The name on my girlfriend's passport was Jillian. To an Arab unfamiliar with Roman script, the words must have looked similar. The others had been turned back because the women were neither married nor related. So I nodded and the officer cheerfully stamped us through.
At that moment I grasped what the rights organisations mean when they talk of gender discrimination. In the Saudi kingdom, a woman is defined only by her relationship to a man: sister, wife, mother, daughter. With no identity of her own, she has no right to passport, vote or driving licence. Women can't drive in Saudi Arabia. They sit in the back like dogs.
As we joined the baking desert highway that led dead straight for more than two thousand miles, Jilly climbed into the back seat and stayed there for three days. At petrol stations, she closed the curtains and covered herself in a veil. When we passed through a town, Saudi men crowded round the vehicle to peer at her, like flies.
Every fifty miles or so we passed a little village, carved out of the brown desert dust. Beside each one was a neat pile of wrecked cars. Not old bangers, but brand new Mercedes and BMWs, driven at breakneck speed, dented and abandoned. Driven by men in a country that doesn't permit a woman to drive as much as a golf cart.
Beside us ran the huge pipeline carrying the welath that supports both our own civilisation and the Saudi regime. It's a country formed by an unholy merger between the feudal and the fundamentalist. A country without freedom of expression, religion or association, without political parties and where justice is articulated by brutal capital and corporal punishment. This is the regime which gave birth to Al-Qaeda, and to which our Queen and Government have once more pledged eternal friendship.
Back beside that other symbol of Western civilisation, the Roman Wall, I reflected on our democracy's fundamental freedom: to believe what we like and say what we believe. I guess that's why you can read this today.