The first, even more serious one was making the promise to Alice.

After that my life settled into a busy routine. The Spook taught me fast and made me write until my wrist ached and my eyes stung.

One afternoon he took me to the far end of the village, beyond the last stone cottage to a small circle of willow trees, which are called ‘withy trees’ in the County. It was a gloomy spot and there, hanging from a branch, was a rope. I looked up and saw a big brass bell.

‘When somebody needs help,’ said the Spook, ‘they don’t come up to the house. Nobody comes unless they’re invited. I’m strict about that. They come down here and ring that bell. Then we go to them.’

The trouble was that even after weeks had gone by, nobody came to ring the bell, and I only ever got to go further than the western garden when it was time to fetch the weekly provisions from the village. I was lonely too, missing my family, so it was a good job the Spook kept me busy – that meant I didn’t have time to dwell on it. I always went to bed tired and fell asleep as soon as my head hit the pillow.

The lessons were the most interesting part of each day but I didn’t learn much about ghasts, ghosts and witches. The Spook had told me that the main topic in an apprentice’s first year was boggarts, together with such subjects as botany, which meant learning all about plants, some of which were really useful as medicines or could be eaten if you had no other food. But my lessons weren’t just writing. Some of the work was just as hard and physical as anything I’d done back home on our farm.

It started on a warm, sunny morning, when the Spook told me to put away my notebook and led the way towards his southern garden. He gave me two things to carry: a spade and a long measuring rod.

‘Free boggarts travel down leys,’ he explained. ‘But sometimes something goes wrong. It can be the result of a storm or maybe even an earthquake. In the County there hasn’t been a serious earthquake in living memory but that doesn’t matter, because leys are all interconnected and something happening to one, even a thousand miles away, can disturb all the others. Then boggarts get stuck in the same place for years and we call them "naturally bound". Often they can’t move more than a few dozen paces in any direction and they cause little trouble. Not unless you happen to get too close to one. Sometimes, though, they can be stuck in awkward places, close to a house or even inside one. Then you might need to move the boggart from there and artificially bind it elsewhere.’

‘What’s a ley?’ I asked.

‘Not everybody agrees, lad,’ he told me. ‘Some think they’re just ancient paths that crisscross the land, the paths our forefathers walked in ancient times when men were real men and darkness knew its place. Health was better, lives were longer and everyone was happy and content.’

‘What happened?’

‘Ice moved down from the north and the earth grew cold for thousands of years,’ the Spook explained. ‘It was so difficult to survive that men forgot everything they’d learned. The old knowledge was unimportant. Keeping warm and eating was all that mattered. When the ice finally pulled back, the survivors were hunters dressed in animal skins. They’d forgotten how to grow crops and husband animals. Darkness was all-powerful.

‘Well, it’s better now, although we still have a long way to go. All that’s left of those times are the leys, but the truth is they’re more than just paths. Leys are really lines of power far beneath the earth. Secret invisible roads that free boggarts can use to travel at great speed. It’s these free boggarts that cause the most trouble. When they set up home in a new location, often they’re not welcome. Not being welcome makes them angry. They play tricks – sometimes dangerous tricks – and that means work for us. Then they need to be artificially bound in a pit. Just like the one that you’re going to dig now…

‘This is a good place,’ he said, pointing at the ground near a big, ancient oak tree. ‘I think there should be enough space between the roots.’

The Spook gave me a measuring rod so that I could make the pit exactly six feet long, six feet deep and three feet wide. Even in the shade it was too warm to be digging and it took me hours and hours to get it right because the Spook was a perfectionist.

After digging the pit, I had to prepare a smelly mixture of salt, iron filings and a special sort of glue made from bones.

‘Salt can burn a boggart,’ said the Spook. ‘Iron, on the other hand, earths things: just as lightning finds its way to earth and loses its power, iron can sometimes bleed away the strength and substance of things that haunt the dark. It can end the mischief of troublesome boggarts. Used together, salt and iron form a barrier that a boggart can’t cross. In fact salt and iron can be useful in lots of situations.’

After stirring the mixture up in a big metal bucket, I used a big brush to line the inside of the pit. It was like painting but harder work, and the coating had to be perfect in order to stop even the craftiest boggart from escaping.

‘Do a thorough job, lad,’ the Spook told me. ‘A boggart can escape through a hole no bigger than a pinhead.’

Of course, as soon as the pit was completed to the Spook’s satisfaction, I had to fill it in and begin again. He had me digging two practice pits a week, which was hard, sweaty work and took up a lot of my time. It was a bit scary too because I was working near pits that contained real boggarts, and even in daylight it was a creepy place. I noticed that the Spook never went too far away though, and he always seemed watchful and alert, telling me you could never take chances with boggarts even when they were bound.

The Spook also told me that I’d need to know every inch of the County – all its towns and villages and the quickest route between any two points. The trouble was that although the Spook said he had lots of maps upstairs in his library, it seemed I always had to do things the hard way, so he started me off by making me draw a map of my own.

At its centre was his house and gardens and it had to include the village and the nearest of the fells. The idea was that it would gradually get bigger to include more and more of the surrounding countryside. But drawing wasn’t my strong point, and as I said, the Spook was a perfectionist so the map took a long time to grow. It was only then that he started to show me his own maps, but he made me spend more time carefully folding them up afterwards than actually studying them.

I also began to keep a diary. The Spook gave me another notebook for this, telling me for the umpteenth time that I needed to record the past so that I could learn from it. I didn’t write in it every day, though; sometimes I was too tired and sometimes my wrist was aching too much from scribbling at speed in my other notebook, while trying to keep up with what the Spook said.

Then, one morning at breakfast, when I’d been staying with the Spook for just one month, he asked, ‘What do you think so far, lad?’

I wondered if he were talking about the breakfast. Perhaps there’d be a second course to make up for the bacon, which had been a bit burnt that morning. So I just shrugged. I didn’t want to offend the boggart, which was probably listening.

‘Well, it’s a hard job and I wouldn’t blame you for deciding to give it up now,’ he said. ‘After the first month’s passed, I always give each new apprentice the chance to go home and think very carefully about whether he wants to carry on or not. Would you like to do the same?’

I did my best not to seem too eager but I couldn’t keep the smile off my face. The trouble was, the more I smiled the more miserable the Spook looked. I got the feeling that he wanted me to stay but I couldn’t wait to be off. The thought of seeing my family again and getting to taste Mam’s cooking seemed like a dream.