One of the great moments of my student life was opening the door and seeing visitors step back, shocked. I’d shaved my hair off to an eighth of an inch. It felt like velvet but looked spiky and hard. It was all down to Ulrike Meinhof, co-founder with Andreas Baader of the Red Army Faction, who’d just hanged herself in Stammheim prison, in Germany.

My friends liked my haircut as we conflated Ulrike the martyr with images of a mullet-haired Jane Fonda raising her fist against the US army on behalf of the tortured Viet Cong. I was reminded of that haircut — and my shocked visitors — by the Prime Minister’s speech in Birmingham this week, when he said that the country needs ‘to confront a tragic truth’ that there are people born and raised here ‘who don’t really identify with Britain’.

Many of us white British middle-class students in the 1970s didn’t identify with Britain either. Our heroes were German terrorists and the IRA, men and, more excitingly, women who were fighting, or rather murdering, for freedom. If you had asked me why I was supporting urban guerrillas who’d massacred athletes at the Munich Olympics, I would have been unable to say. I never asked myself why the extreme left in West Germany didn’t just hop over the wall into the bosom of Erich Honecker, leader of the East German dictatorship waiting on the other side.

The Baader-Meinhof gang had a good excuse for being messed up; they have been termed ‘Hitler’s children’. Andreas Baader’s father returned from university on the day the students who distributed the ‘White Rose’ leaflets against Hitler were executed. Young Baader heard him say, ‘How can we stop this?’ It seemed to me that, in his violence against West Germany, Andreas was taking the correct response to his father’s failure. Photos of him with his lover, Gudrun Ensslin, a Marianne Faithfull lookalike, showed us romantic outsiders; bombing, burning and kidnapping in protest against their parents’ past crimes and current injustices. My infatuation was irrational, but no ‘counter-narrative’ from anyone in government would have persuaded me out of it.

I don’t have any children, so I lack detailed knowledge about the thoughts and aspirations of the modern teenager, but from my past I think I can understand why a large number of them choose to band together to assist the murderous Islamic State. The majority of them come from Middle Eastern countries, but about 2,300 are westerners. UK Security services say that since March this year, 600 have been British. Around 60 are teenage girls. The Prime Minister puts this down to ‘issues of identity and failures of integration’.

I think it is about deep failures of identity, but I’m not sure that the PM really understands psychology, or that the government can tackle problems of poor parenting which have nothing to do with poverty and class. You don’t have to be Muslim to be a dangerously unhappy teenager. I was adopted as a baby by very good people, but they were the last generation brought up by Victorians and mistook my sadness for ingratitude. Aged 21, hoping for a new, more successful attachment, I met my original mother. She wasn’t interested. I rang my natural grandmother, who told me, ‘Your birth was the worst thing that happened to our family.’ I was almost overwhelmed by feelings of rejection. I also had feelings of intense guilt at the pain my birth had caused.

According to John Horgan, a psychologist at the University of Massachusetts’s Centre for Terrorism and Security Studies, ‘Foreign fighters are driven to join Isis by the need to belong to something special. They want to find something meaningful for their life. Some are seeking redemption.’

Feeling I fitted in nowhere without proper closeness to my parents, I began searching for a more worthy identity. The advice ‘Just be yourself’, which I seemed to hear a lot, was terrible to my ears: I had no idea who I was. Some young people who feel displaced or suffer self-loathing take up drink, drugs and underage sex; some go into showbusiness; others, like me, take the trajectory of terrorism. What I wanted was some kind of belonging and this was most easily found in a group. This coterie had to consist of other outsiders.

For members of Isis, belonging to a group means promoting the idea of a perfect caliphate where they will entirely belong. I chose the IRA, at that time apparently taking on the British empire from their council houses in Derry, and erudite young Germans, who set about robbing banks for socialism. We were all victims together, fighting back in small battalions against crushing forces. I could see that my heroes’ actions were often vicious, but justified them because they sprang from historic injuries.

Throughout my obsession, I never took my troubles to the Troubles or left my bedroom to tote a Kalashnikov on the beach, but I did move to live in a communist dictatorship: Poland. I was quickly locked up and realised my mistake. I came home a lot more circumspect about the then pervasive Soviet propaganda. I was also saved from annihilation, although I often wanted it, because I yearned for conventional success. I wanted to be a journalist, and having a practical ambition helped to overcome my nihilism.

In 1985, 50 years after the extremist Nuremburg Laws were passed by the Nazis, I visited that city to talk to the older generation. Most were pleasantly evasive — memory loss can be useful — but one old lady still hated our RAF, accusing it of war crimes. She insisted that Hitler had known nothing about the Holocaust, which she termed ‘those things’, claiming it was all down to Himmler. I was fascinated by her visceral hatred because it gave me a true glimpse of her past life; a young girl deeply engrossed in Hitler. For whatever tortured reasons, she was still in her mental cell, seduced by dark, narcissistic violence, backing a regime dedicated to death.

Sitting in her garden chair in the pleasant care-home, she had never escaped from the terrorism of the mind, with its compulsive need for skewed thinking and denial of truth. I had, but it had taken years and some luck.