Once he'd reached the gate, he walked straight up to the attendant at the desk.

'Good morning, captain,' she said, even before he'd opened his passport. 'I hope you have a pleasant flight.'

He walked out on to the tarmac, climbed the steps to the aircraft and entered an empty first-class cabin.

'Good morning, Captain May,' said an attractive young woman. 'My name is Annabel Carrick. I'm the senior stewardess.'

The uniform, and the discipline, made it feel like being back in the army, even if he was up against a different enemy this time, or was it, as Sir Alan had suggested, the same one?

'May I show you to your seat?'

'Thank you, Miss Carrick,' he said as she led him to the rear of the first-class cabin. Two empty seats, but he knew only one of them would be occupied. Sir Alan didn't leave that sort of thing to chance.

'The first leg of the flight should take about seven hours,' said the stewardess. 'Can I get you a drink before we take off, captain?'

'Just a glass of water, thank you.' He took off his peaked cap and put it on the seat beside him, then placed the briefcase on the floor under his seat. He had been told not to open it until the plane had taken off, and to be certain no one could see what he was reading. Not that the file mentioned Martinez by name from the first page to the last, referring to him only as 'the subject'.

A few moments later, the first passengers began to make their way on to the plane, and for the next twenty minutes they located their seats, placed their bags in the overhead lockers, shed their coats, and some of them their jackets, settled themselves down, enjoyed a glass of champagne, clicked on their seat belts, selected a newspaper or magazine, and waited for the words, 'This is your captain speaking.'

Harry smiled at the thought of the captain being taken ill during the flight and Miss Carrick running back to ask him for his assistance. How would she react when he told her that he'd served in the British merchant navy and the US army, but never the air force?

The plane taxied on to the runway, but Harry didn't unlock his briefcase until they were in the air and the captain had turned off the seat-belt sign. He pulled out a thick file, opened it and began to study its contents, as if he was preparing for an exam.

It read like an Ian Fleming novel; the only difference was that he was cast in the role of Commander Bond. As Harry turned the pages, Martinez's life unfolded in front of him. When he took a break for dinner, he couldn't help thinking that Emma was right, they should never have allowed Sebastian to go on being involved with this man. It was far too big a risk.

However, he'd agreed with her that if at any time he felt their son's life was in danger, he would return to London on the next plane with Sebastian sitting beside him. He glanced out of the window. Instead of flying south, he and William Warwick were meant to be on their way up north that morning to begin a book tour. He'd been looking forward to meeting Agatha Christie at the Yorkshire Post literary lunch. Instead, he was heading to South America, hoping to avoid Don Pedro Martinez.

He closed the file, returned it to the briefcase, slid it under the seat and drifted into a light sleep, but 'the subject' never left him. By the age of fourteen, Martinez had left school and begun life as an apprentice in a butcher's shop. He was fired a few months later (reason unknown), and the only skill he took with him was how to dismember a carcase. Within days of becoming unemployed, the subject had drifted into petty crime, including theft, mugging, and raiding slot machines, which ended with him being arrested and sent to prison for six months.

While he was locked up, he shared a cell with Juan Delgado, a minor criminal who'd spent more years behind bars than on the outside. After Martinez had served his sentence, he joined Juan's gang and quickly became one of his most trusted lieutenants. When Juan was arrested yet again and returned to jail, Martinez was left in charge of his dwindling empire. He was seventeen at the time, the same age as Sebastian, and he looked set for a life of crime. But destiny took an unexpected turn when he fell in love with Consuela Torres, a telephone operator who worked on the international exchange. However, Consuela's father, a local politician who was planning to run for mayor of Buenos Aires, made it clear to his daughter that he didn't want a petty criminal as a son-in-law.

Consuela ignored her father's advice, married Pedro Martinez, and gave birth to four children, in the correct South American order, three boys followed by a girl. Martinez finally gained his father-in-law's respect when he raised the necessary cash to fund his victorious election campaign for mayor.

Once the mayor had taken up residence in city hall, there were no municipal contracts that didn't pass through Martinez's hands, always with an added 25 per cent 'service charge'. However, it wasn't long before the subject became bored with both Consuela and local politics, and began to expand his interests when he worked out that a European war meant there would be endless opportunities for those who could claim neutrality.

Although Martinez was naturally inclined to support the British, it was the Germans who offered him the opportunity to turn his small fortune into a large one.

The Nazi regime needed friends who could deliver, and although the subject was only twenty-two when he first turned up in Berlin with an empty order book, he left a couple of months later with demands for everything from Italian pipelines to a Greek oil tanker. Whenever he attempted to close a deal, the subject would make it known that he was a close friend of Reichsfuhrer Heinrich Himmler, the head of the SS, and had met Herr Hitler himself on several occasions.

For the next ten years, the subject slept in aeroplanes and on ships, trains, buses and once even a horse and cart, as he travelled around the world, ticking off a long list of German requirements.

His meetings with Himmler became more frequent. Towards the end of the war, when an Allied victory looked inevitable and the Reichsmark collapsed, the SS leader began paying the subject in cash; crisp English five-pound notes, hot off the Sachsenhausen press. The subject would then cross the border and bank the money in Geneva, where it was converted into Swiss francs.

Long before the war had ended, Don Pedro had amassed a fortune. But it was not until the Allies were within striking distance of the German capital that Himmler offered him the opportunity of a lifetime. The two men shook hands on the deal, and the subject left Germany with twenty million pounds in forged five-pound notes, his own U-boat, and a young lieutenant from Himmler's personal staff. He never set foot in the fatherland again.

On his arrival back in Buenos Aires, the subject purchased an ailing bank for fifty million pesos, hid his twenty million pounds in the vaults, and waited for the surviving members of the Nazi hierarchy to turn up in Buenos Aires and cash in their retirement policy.

The ambassador stared down at the ticker tape machine as it clattered away in the far corner of his office.

A message was being sent direct from London. But as with all Foreign Office directives, he would need to read between the lines, because everyone knew that the Argentinian secret service would be getting the message at the same time, in an office just a hundred yards up the road.

Peter May, the captain of the England cricket team, will be opening the batting on the first day of the Lord's Test match this Saturday at ten o'clock. I have two tickets for the match, and I hope Captain May will be able to join you.