PROLOGUE

      I was sixteen when I found out. We were going on holiday to Scotland with another family. The car was already loaded at 6.30 a.m. with everything from frozen food to an inflatable dinghy. My mother, my brother and I were standing in the kitchen, ready to leave the moment my father said, let’s go, so as not to start the twelve-hour drive on a bad note – we would have to keep our nerve for his overtaking manoeuvres on the A9. Mum said almost as an aside that we were not to be surprised if we heard the other paterfamilias refer to Grandpa as her step-father – why? – because he is. ‘Grandpa adopted Lizzie and me when he married Granny. Our real father was her first husband, and he died when we were very small.’ And then my father said, let’s go.

      My world did not fall apart. I did not feel betrayed or deceived because we had not been told sooner. I did not feel as though my own sense of identity had been weakened. As the August countryside passing by in car window-sized frames gave way to the purple hills of the Highlands, I wondered if my relationship with my grandfather would change now he was my step-grandfather. I saw no reason why it should. He was the only one I had ever known – I could not remember my father’s father. We were the only grandchildren he had. Even though we were not related by blood he could never be anything other than our Grandpa. The real surprise was that our mother was not entirely the person I thought she was. I had passed through that stage of early adolescence when you think your parents don’t know anything about you, and I was beginning to realize how little I knew about them. Family gatherings thereafter became opportunities to observe the newly revealed relationships at work.

      John Winthrop Hackett, my step-grandfather, was a great man. He was a career soldier who had reached the rank of major at the outbreak of the Second World War. He had what they call a ‘good war’ and was a brigadier by the end. He had shown great bravery, receiving wounds and decorations in equal measure. As a leader he had inspired enduring devotion in his subordinates, not least because of his maverick attitude towards his own superiors. He rose to the rank of full general and commanded the British Army of the Rhine during the deep mid-winter of the Cold War. He had been commander-in-chief of the British forces in Northern Ireland in the late 1960s and still featured in those IRA assassination wish-lists that were discovered scribbled on Rizla papers and the backs of envelopes bearing the new decimal stamps. He was dubbed a Knight Grand Cross of the Order of Bath. He had even been tipped for the top army job, but a frank letter to The Times on the ability of NATO to withstand a non-nuclear offensive, in which he asserted that Russian tanks would be in Paris in forty-eight hours, so infuriated his political masters that he was denied, it is said, this final promotion.

      He was also a scholar. He had read Greats at New College, Oxford, having the precocity to complete that degree in two years and sit the finals for one in History the following summer. It was said that he did not know which to be, a soldier or a don, and that he became a soldier in a prolonged bout of donnish absent-mindedness. Even after becoming a soldier he gained a B. Litt. for his thesis on Saladin’s campaign against the Principality of Antioch in 1188. After he retired from the army he became Principal of King’s College, London. It was his last public appointment. Granny and Grandpa lived in a narrow house on Campden Hill that had a security grille in front of the garden doors and a twisting wooden banister, perfect for sliding down, that I scratched from top to bottom with the buckle of my belt.

      In 1975 Grandpa retired and he and Granny moved to a mill house in the Cotswolds that they had bought some years previously. It was an event that had an impact on my family too: we had to vacate the mill. We had lived there for five years, and it was the longest that we had stayed anywhere. My father was also a career soldier, a major at the time of his secondment to the Wessex Yeomanry in Cirencester, which was to be his last posting. I was six when we moved in. I had already had four different homes, three of which I could remember, army married quarters in Canada, Dorchester and Sevenoaks. While I remembered them all with affection, Coberley Mill was the best place a boy who loved woods and streams could possibly find himself. Leaving a house so old and so alive, the creaking boards below