The Underground stations served as air-raid shelters during the Second World War. They were never intended to, but so many people flocked into them that the authorities simply turned a blind eye.

Down we went on the escalator into the bowels of Piccadilly. I had something of a shake going on. I fancied a bit of excitement, truly, but not getting blown up by a bomb.

‘How long do air raids generally last?’ I asked Hugo Rune as we descended on the escalator.

‘That depends very much on whether they are real air raids or not,’ he said.

‘You mean sometimes they are false alarms?’

‘I mean no such thing. Sometimes the Ministry of Serendipity wants the streets cleared for reasons of its own.’

‘What kind of reasons might these be?’

Mr Rune did tappings at his nose and pointed to a poster that read WALLS HAVE EARS.

That phrase rang a terrible bell, from my recent experiences in enemy-occupied Brentford. But I asked Mr Rune what it meant.

‘Spies,’ he whispered into my ear. ‘Fifth Columnists. Quizlings and beings of that nature, generally.’

‘There are German spies here?’ I whispered back and then did glancings all around.

Hugo Rune nodded and whispered some more. ‘Regarding air raids. When the air-raid siren sounds, all non-London-serving military personnel, essential services, ARP, Home Guard, police, ambulance services, firefighters and so on, must adjourn to the shelters at once. This is the law. Martial law. Anyone caught on the streets can be shot as a looter.’

‘That is never true,’ I said.

‘Oh yes it is,’ the Perfect Master whispered. ‘There is much that history does not record about this war. The Fire Service Secret Priority List, for instance.’ And he went on in whispered words to explain just what that was. ‘When the bombs start to drop and the calls come in to the fire stations, the gallant lads are expected to respond to these calls in order of priority – hospitals, Government buildings, food supply depots and suchlike. Now recall that the streets are deserted and there is no one to watch in which direction the appliances travel. The Secret Priority List in the station house does not list the Government-approved priority targets for fire extinguishing. On the contrary, it lists pubs, jewellery shops, furriers, high-class tailors and sweet shops. You may draw your own conclusions as to why.’

‘That is the most cynical thing I have ever heard you say,’ I said to Hugo Rune. ‘Those firemen are heroes. I have been told that my own father was a fireman here in London during the Blitz.’ And that made me think about my father. About meeting him. Because he was here, somewhere in London, right here and now. Alive.

Hugo Rune could tell what I was thinking and he mouthed ‘no’ towards me. ‘You must understand this, Rizla,’ he went on, ‘war brings out the best in people, the noble virtues. But it also brings out the worst. And the fear that the next minute may be your last does not always engender a charitable disposition.’

‘I am disgusted by your words,’ I said. ‘And also,’ and I fanned at my nose, ‘by this pong. The London populace that shelters here from the bombings is of a somewhat unwashed persuasion, I am thinking.’

‘Indeed.’ And Hugo Rune applied a nosegay to his sniffer. ‘But if your love is for a cockney singalong about getting your knees up and eating jellied eels, then this is the place to be.’

‘We are losing time here,’ I said. ‘If you wish to solve this case by the end of the day we have to get out of here at the hurry-up.’

‘And so we will, Rizla. Now follow me.’

And I followed Hugo Rune, down onto the platform of Piccadilly Underground Station, through the hurly-burly and hustle and bustle of cockney costermongers, pearly kings and queens, chimney-sweeping lads and a whole host of colourful period characters who surely should have peopled a Victorian music hall rather than a nineteen-forties Underground station.

‘Style never dates,’ said Hugo Rune, as if in answer to my unasked question. ‘Now follow me further.’

And we left the platform’s edge and stepped down onto the track.

‘Oh no!’ I cried. ‘We shall surely be electrocuted or run over by a train. This is not a good idea at all.’

‘Be not so timid, Rizla,’ called Himself, striding away with vigour. ‘The power is switched off during air raids. We have a good twenty minutes. Hurry now, the fun-fur-collared anorak of dread masks not the tattooed shoulder of Talula the hula-hula girl from Kealakekua, Hawaii. No siree. By golly.’

And so I shrugged and followed Mr Rune.

I am still uncertain as to how he created the light which shone ahead of us along the darkness of the tunnel. It appeared to flow from the pommel of his stout stick, but as to how I do not know, because I did not ask.

‘Where are we heading to?’ I did ask, tripping for the umpteenth time and stumbling about.

‘Only to Whitechapel.’

‘What?’ I replied. ‘That is miles away, surely.’

‘Naught but a brisk stroll. Are you tooled-up?’

And I had to ask just what he meant.

‘Are you armed, Rizla? As my good friend Mr Sherlock Holmes used to say, “Always carry a firearm east of Aldwych”.’

‘You never knew-’ But I did not bother to finish. I stumbled and bumbled along behind Mr Rune, who, it seemed to me, although I might well have been mistaken, took some pleasure in my stumblings and bumblings. By his unstifled laughter.

‘It is not funny, me falling down,’ I told him.

‘Nearly there, Rizla,’ he replied. And then he chuckled some more.

And eventually we reached Whitechapel Station. I now had very grazed knees and was not at the peak of my general unfailing cheerfulness. ‘You can be a thoroughgoing rotter at times,’ I told Hugo Rune. ‘On this matter I agree with little Mr McMurdo.’

We hustled and bustled through many more cockneys and climbed over the turnstiles when no station staff were watching and reached daylight in time to hear the ‘all clear’.

Which somehow seemed so convenient.

I looked up at Hugo Rune.

And then I shook my head.

‘Well, you wanted excitement,’ he said. ‘Now let’s press on.’ And press on so we did.

I had never been to this area of London before and I must say that it had taken a terrible pounding. But apparently not today, as I saw no signs of smoke, nor gallant firemen with pockets full of diamonds and guts all full of liberated beer.

‘This is Jack the Ripper territory,’ I said to Hugo Rune.

And the great man smiled and said, ‘Don’t get me going on him.’ And then he pointed with his cane and said, ‘That way, down the Radcliffe Highway.’

At length we reached a rather delightful house. It had blooming wisteria all about its door, which considering the month of the year it really should not have. And it had flowering chrysanthemums and hollyhocks and tulips, roses and Rafflesia arnoldii in its neat little trimmed front garden. The house was constructed of London Stock, beneath a roof of Northampton Slate. And there was something altogether musical about it. The front door was of Henry wood and the windows, Philip glass.

I noted also a doorstop of Sly stone and that the afternoon sun angling down gave the front garden the look of a dusty spring field.

‘Stop that as soon as you like!’ said Mr Rune, and he rapped with his stout stick on the door.

The lady who answered his rappings was beauteous to behold. Her hair was simply red and her coat was deacon blue. It seemed we had just caught her as she was on her way out, and her face was flushed and pink.

Mr Rune made faces at me and introduced himself.

‘I know who you are,’ I told him.

‘I am introducing myself to this lady,’ he said.

‘I am sorry. I got confused.’ I scuffed my heels upon the doorstop and noticed that my brogues where Arthur brown.