'What?' said Harry blankly.

'He left!' said Mrs Figg, wringing her hands. 'Left to see someone about a batch of cauldrons that fell off the back of a broom! I told him I'd flay him alive if he went, and now look! Dementors! It's just lucky I put Mr Tibbles on the case! But we haven't got time to stand around! Hurry, now, we've got to get you back! Oh, the trouble this is going to cause! I will kill him!'

'But — ' The revelation that his batty old cat-obsessed neighbour knew what Dementors were was almost as big a shock to Harry as meeting two of them down the alleyway. 'You're — you're a witch ?'

'I'm a Squib, as Mundungus knows full well, so how on earth was I supposed to help you fight off Dementors? He left you completely without cover when I'd warned him — '

'This Mundungus has been following me? Hang on — it was him ! He Disapparated from the front of my house!'

'Yes, yes, yes, but luckily I'd stationed Mr Tibbles under a car just in case, and Mr Tibbles came and warned me, but by the time I got to your house you'd gone — and now — oh, what 's Dumbledore going to say? You!' she shrieked at Dudley, still supine on the alley floor. 'Get your fat bottom off the ground, quick!'

'You know Dumbledore?' said Harry, staring at her.

'Of course I know Dumbledore, who doesn't know Dumbledore? But come on — I'll be no help if they come back, I've never so much as Transfigured a teabag.'

She stooped down, seized one of Dudley's massive arms in her wizened hands and tugged.

'Get up, you useless lump, get up !'

But Dudley either could not or would not move. He remained on the ground, trembling and ashen-faced, his mouth shut very tight.

'I'll do it.' Harry took hold of Dudley's arm and heaved. With an enormous effort he managed to hoist him to his feet. Dudley seemed to be on the point of fainting. His small eyes were rolling in their sockets and sweat was beading his face; the moment Harry let go of him he swayed dangerously.

'Hurry up!' said Mrs Figg hysterically.

Harry pulled one of Dudley's massive arms around his own shoulders and dragged him towards the road, sagging slightly under the weight. Mrs Figg tottered along in front of them, peering anxiously around the corner.

'Keep your wand out,' she told Harry, as they entered Wisteria Walk. 'Never mind the Statute of Secrecy now, there's going to be hell to pay anyway, we might as well be hanged for a dragon as an egg. Talk about the Reasonable Restriction of Underage Sorcery . . . this was exactly what Dumbledore was afraid of — What's that at the end of the street? Oh, it's just Mr Prentice . . . don't put your wand away, boy, don't I keep telling you I'm no use?'

It was not easy to hold a wand steady and haul Dudley along at the same time. Harry gave his cousin an impatient dig in the ribs, but Dudley seemed to have lost all desire for independent movement. He was slumped on Harry's shoulder, his large feet dragging along the ground.

'Why didn't you tell me you're a Squib, Mrs Figg?' asked Harry, panting with the effort to keep walking. 'All those times I came round your house — why didn't you say anything?'

'Dumbledore's orders. I was to keep an eye on you but not say anything, you were too young. I'm sorry I gave you such a miserable time, Harry, but the Dursleys would never have let you come if they'd thought you enjoyed it. It wasn't easy, you know . . . but oh my word,' she said tragically, wringing her hands once more, 'when Dumbledore hears about this — how could Mundungus have left, he was supposed to be on duty until midnight — where is he? How am I going to tell Dumbledore what's happened? I can't Apparate.'

'I've got an owl, you can borrow her.' Harry groaned, wondering whether his spine was going to snap under Dudley's weight.

'Harry, you don't understand! Dumbledore will need to act as quickly as possible, the Ministry have their own ways of detecting underage magic, they'll know already, you mark my words.'

'But I was getting rid of Dementors, I had to use magic — they're going to be more worried about what Dementors were doing floating around Wisteria Walk, surely?'

'Oh, my dear, I wish it were so, but I'm afraid — MUNDUNGUS FLETCHER, I AM GOING TO KILL YOU!'

There was a loud crack and a strong smell of drink mingled with stale tobacco filled the air as a squat, unshaven man in a tattered overcoat materialised right in front of them. He had short, bandy legs, long straggly ginger hair and bloodshot, baggy eyes that gave him the doleful look of a basset hound. He was also clutching a silvery bundle that Harry recognised at once as an Invisibility Cloak.

' 'S'up, Figgy?' he said, staring from Mrs Figg to Harry and Dudley. 'What 'appened to staying undercover?'

'I'll give you undercover !' cried Mrs Figg. 'Dementors, you useless, skiving sneak thief!'

'Dementors?' repeated Mundungus, aghast. 'Dementors, 'ere?'

'Yes, here, you worthless pile of bat droppings, here!' shrieked Mrs Figg. 'Dementors attacking the boy on your watch!'

'Blimey,' said Mundungus weakly, looking from Mrs Figg to Harry, and back again. 'Blimey, I — '

'And you off buying stolen cauldrons! Didn't I tell you not to go? Didn 't I?'

'I — well, I —' Mundungus looked deeply uncomfortable. 'It — it was a very good business opportunity see — '

Mrs Figg raised the arm from which her string bag dangled and whacked Mundungus around the lace and neck with it; judging by the clanking noise it made it was full of cat food.

'Ouch — gerroff — gerroff, you mad old bat! Someone's gotta tell Dumbledore!'

'Yes — they — have!' yelled Mrs Figg, swinging the bag of cat food at every bit of Mundungus she could reach. 'And — it — had — better — be — you — and — you — can — tell — him — why — you — weren't — there — to — help!'

'Keep your 'airnet on!' said Mundungus, his arms over his head, cowering. 'I'm going, I'm going!'

And with another loud crack, he vanished.

'I hope Dumbledore murders him!' said Mrs Figg furiously. 'Now come on, Harry, what are you waiting for?'

Harry decided not to waste his remaining breath on pointing out that he could barely walk under Dudley's bulk. He gave the semi-conscious Dudley a heave and staggered onwards.

'I'll take you to the door,' said Mrs Figg, as they turned into Privet Drive. 'Just in case there are more of them around . . . oh my word, what a catastrophe . . . and you had to fight them off yourself . . . and Dumbledore said we were to keep you from doing magic at all costs . . . well, it's no good crying over spilt potion, I suppose . . . but the cat's among the pixies now.'

'So,' Harry panted, 'Dumbledore's . . . been having . . . me followed?'

'Of course he has,' said Mrs Figg impatiently. 'Did you expect him to let you wander around on your own after what happened in June? Good Lord, boy, they told me you were intelligent . . . right . . . get inside and stay there,' she said, as they reached number four. 'I expect someone will be in touch with you soon enough.'

'What are you going to do?' asked Harry quickly.

'I'm going straight home,' said Mrs Figg, staring around the dark street and shuddering. 'I'll need to wait for more instructions. Just stay in the house. Goodnight.'

'Hang on, don't go yet! I want to know — '

But Mrs Figg had already set off at a trot, carpet slippers flopping, string bag clanking.

'Wait!' Harry shouted after her. He had a million questions to ask anyone who was in contact with Dumbledore; but within seconds Mrs Figg was swallowed by the darkness. Scowling, Harry readjusted Dudley on his shoulder and made his slow, painful way up number four's garden path.

The hall light was on. Harry stuck his wand back inside the waistband of his jeans, rang the bell and watched Aunt Petunia's outline grow larger and larger, oddly distorted by the rippling glass in the front door.

'Diddy! About time too, I was getting quite — quite — Diddy, what 's the matter? '

Harry looked sideways at Dudley and ducked out from under his arm just in time. Dudley swayed on the spot for a moment, his face pale green . . . then he opened his mouth and vomited all over the doormat.

'DIDDY! Diddy, what's the matter with you? Vernon? VERNON!'

Harry's uncle came galumphing out of the living room, walrus moustache blowing hither and thither as it always did when he was agitated. He hurried forwards to help Aunt Petunia negotiate a weak-kneed Dudley over the threshold while avoiding stepping in the pool of sick.

'He's ill, Vernon!'

'What is it, son? What's happened? Did Mrs Polkiss give you something foreign for tea?'

'Why are you all covered in dirt, darling? Have you been lying on the ground?'

'Hang on — you haven't been mugged, have you, son?'

Aunt Petunia screamed.

'Phone the police, Vernon! Phone the police! Diddy, darling, speak to Mummy! What did they do to you?'

In all the kerfuffle nobody seemed to have noticed Harry, which suited him perfectly. He managed to slip inside just before Uncle Vernon slammed the door and, while the Dursleys made their noisy progress down the hall towards the kitchen, Harry moved carefully and quietly towards the stairs.

'Who did it, son? Give us names. We'll get them, don't worry.'

'Shh! He's trying to say something, Vernon! What is it, Diddy? Tell Mummy!'

Harry's foot was on the bottom-most stair when Dudley found his voice.

'Him. '

Harry froze, foot on the stair, face screwed up, braced for the explosion.

'BOY! COME HERE!'

With a feeling of mingled dread and anger, Harry removed his foot slowly from the stair and turned to follow the Dursleys.

The scrupulously clean kitchen had an oddly unreal glitter after the darkness outside. Aunt Petunia was ushering Dudley into a chair; he was still very green and clammy-looking. Uncle Vernon was standing in front of the draining board, glaring at Harry through tiny, narrowed eyes.

'What have you done to my son?' he said in a menacing growl.

'Nothing,' said Harry, knowing perfectly well that Uncle Vernon wouldn't believe him.

'What did he do to you. Diddy?' Aunt Petunia said in a quavering voice, now sponging sick from the front of Dudley's leather jacket. 'Was it — was it you-know-what, darling? Did he use — his thing?'

Slowly, tremulously, Dudley nodded.

'I didn't!' Harry said sharply, as Aunt Petunia let out a wail and Uncle Vernon raised his fists. 'I didn't do anything to him, it wasn't me, it was — '