I might also be welcome for my medical skills. Like all naval expeditions, the ships would carry their own surgeons, but they were a class of unskilled butchers, whose main purpose was to hack off injured limbs too fearfully smashed to preserve. They probably killed more men than they saved. As a physician I was better qualified to help the men, both afloat and ashore, with the many illnesses that sailors and soldiers are heir to. However, as a physician I would have little freedom to carry out the plan I was tentatively forming in my mind. I would need a reason to leave the expedition at some point and venture into the interior of Portugal on my own. I decided I must call on Walsingham.

Never before had I gone willingly to offer my services to Sir Francis. Originally, when I was but sixteen, I had been coerced into his service as a code-breaker and translator by the contrivance of Robert Poley, who had discovered my sex. For a woman to disguise herself as a man was regarded as heresy, and the punishment, as for any form of heresy, was burning at the stake. Threatened with exposure by Poley, I had entered Walsingham’s service in fear and resentment, yet gradually, working under the chief of his agents, Thomas Phelippes, I had found I enjoyed the challenge of breaking new and seemingly impossible codes. They were the most intriguing and exciting of puzzles, and yet they were not mere trivial entertainment. My work with Phelippes was aimed at the protection of the nation and the Queen against our many enemies, principally Spain, France and the Papacy.

When Phelippes trained me in forgery, I was less happy, but many of the ‘projections’, as he and Walsingham called them, required slipping false reports and misleading information in amongst the enemies’ own intercepted papers, and I proved to have a useful skill here as well. When Walsingham had despatched me on other missions, first in England and later in the Low Countries, I had survived and had some small successes – more through accident and luck than through skill on my part. A few times my own clumsiness had nearly cost me dear.

One skill which they had arranged for me to be taught – swordsmanship – I had chosen to improve for my own satisfaction. Since returning from Amsterdam I had spent more time with Master Scannard at the Tower, who had undertaken my original training at Walsingham’s bidding. Although I would never be a master at the skill, nor wish to be, yet I hoped I would no longer fall over the sword Walsingham had provided for me. I did not carry it in London, preferring the simple dagger my father had given me, but if I was going on the Portuguese expedition, I would wear it. Scannard, a man scanty of words and even scantier of praise, conceded that I had made some progress.

To go now to Walsingham and willingly offer to serve him was contrary to everything I had felt before, but it seemed the only way to accomplish what I had in mind to try. He had agreed to see me, and I presented myself in good time at Seething Lane, to be shown into Sir Francis’s office by his chief secretary, Francis Mylles.

‘We have not seen you since last autumn, Kit,’ Mylles said. ‘You are well?’

‘Aye, never better. And you?’

We exchanged the usual pleasantries.

‘Sir Francis will be here shortly,’ Mylles said. ‘If you would not mind waiting?’

As if I should take offence at waiting for the Queen’s Principal Secretary, her most senior advisor after Lord Burghley.

Mylles offered me wine, but I refused, wanting to keep a clear head. Indeed he was gone only a few minutes when Sir Francis appeared, apologising. He looked, as he so often did, tired and ill but resolutely indomitable. I never knew a man so determined to defeat his physical weakness by strength of mind.

‘Kit, my dear boy, it is very good to see you! Has Mylles not offered you wine?’

Before I could object, he was pressing a glass into my hand. As always, it was of the very best quality. He had his sources. However, I took only small sips.

‘The Portuguese expedition, Sir Francis.’

‘Ah.’ He gave me a knowing smile. ‘You are to sail with it, of course.’

It was no surprise to me that he knew. He always seemed to know my affairs before I did.

‘Possibly. Probably. If I can get leave from St Bartholomew’s. My father–,’ I paused. ‘My father has invested in it.’

‘And you are not happy about that.’

I suppose my feelings were writ large on my face.

‘Nay, I am not, but it is done now.’

‘The Queen has invested twenty thousand pounds.’

So the Queen had been persuaded to increase her stake in the venture.

‘The Queen has rather more means than my father and I!’ I should not have said it, but the words were out before I could stop them.

He did not rebuke me, but I apologised quickly.

‘You are concerned, of course,’ he said. ‘And you will go with the expedition to ensure that all is well.’

‘There is little I can do, surely, to ensure that, but my father wishes me to go. Otherwise he would try to go himself, but he is not strong enough. I have no wish to return to Portugal.’

I swallowed hard and Sir Francis nodded. He knew a little of my history, but by no means the most dangerous part.

‘However, I do not want to be merely a passenger.’ I cleared my throat. ‘It would seem a fruitless waste of time. I thought I could perhaps serve you in some way, if there is any mission you want undertaken in Portugal? I know you have agents there already, so perhaps there is no need.’

My voice trailed away. My whole purpose in coming here suddenly seemed foolish. Yet Sir Francis looked at me thoughtfully, not at all dismissive of my suggestion.

‘I see.’ He got up and drew down a rolled-up sheet of heavy paper from a shelf and laid it out on his desk, weighing it down with books and an ink-pot and his little Roman statue.

‘You have probably not yet been told the detailed plans for the expedition, am I right? Yet I know I can trust your discretion. Look here at the map.’

I joined him at the desk. The map covered the area from the southern end of the Bay of Biscay to the Pillars of Hercules, showing the whole of Spain and Portugal, with all the major towns, cities and ports clearly marked, and the courses of the principal rivers. My heart jumped at the sight of the word ‘Coimbra’. My old home, where my father had been a professor of medicine at the university.

‘The Queen wishes the expedition to undertake three main tasks,’ Sir Francis explained, ‘all intended to weaken the power of Spain both in Iberia and abroad. The first I am sure you know: to install Dom Antonio on the throne of Portugal and drive the Spanish from the country.’

I nodded. I had though that was the sole purpose.

‘Secondly, our fleet will destroy as much as possible of the remaining Spanish fleet. The merchant ships armed for war last year in the invading fleet were mostly destroyed, either by our navy or by storms in the Atlantic. Many of the largest warships, however, managed to return to Spain, though the majority were damaged and unfit for war without extensive repairs. Most of the repairs are being carried out here.’

He tapped his finger on Santander, on the southern shore of the Bay of Biscay.

‘More of the ships, some needing minor repairs, are here.’

He pointed to Coruña, out near Cape Finisterre.

‘The route of the expedition, therefore, will be to cross the Bay of Biscay and invest Santander, where the fleet under repair will be fired.’

‘Like the ships in Cadiz,’ I said, ‘two years ago.’

‘Aye.’ He smiled grimly. ‘When Drake singed the King of Spain’s beard, as the common folk like to say.’

‘If they are being repaired, they will be immobilised,’ I ventured.

‘Exactly. It should not be a difficult task. Our fleet will then proceed to Coruña and repeat the attack on the ships there.’