IT IS late in Soho and I am facing down the world dice champion.

The world champ is a former Blue Peter presenter. I have one last die. The champ has a fistful of five. The odds are stacked against me. I roll my one and conceal it under my cup. It is a four — not bad, not good either.

Do I bluff? Do I play it cautious? I narrow my eyes …

I report from the Perudo championships, which were held in the Groucho Club just last night. Perudo? It’s the new poker, so they tell me — a Peruvian game of chance and chutzpah, played with five dice and a lot of gall. It was brought to Britain in the mid-1980s by a hotelier named Cosmo Fry. Cosmo discovered the game in the Lima golf club, where he swiftly became hooked. Second most addictive thing to come out of South America, he calls it.

Cosmo explains to me that the Peruvians play the game with an infinite variety of quirks — different rules in Cuzco from what you get in Iquitos. But it was Cosmo who standardised the play, hired Incan artisans to make the dice and the cups and smuggled it to London two decades ago. Stephen Fry and the late Peter Cook became known devotees.

The beauty of the game? It’s all about spin. The hand you get is the throw of the dice — you conceal it from the table, stake your stake on what you think everyone else has under their cup. It’s luck, but the skill is in the lying.

So I’m sitting on a table of six, it’s the heats, and it’s down to just me and the world champ. I’m good at lying, not so sure about luck.

The champ, by the way, is Konnie Huq, but there’s nothing so strange in this. It’s a bit like how Al Alvarez, the great poetry critic, also happens to be a famous poker player. This is just what ex-Blue Peter presenters do to relax, if you can call this relaxing. Huq’s flustered, she hasn’t been this riled since the Tibet protesters made their grab on the Olympic torch.

"Four fours", I say. But she’s wily. With a cry of "Dudo!" she challenges my four fours. There are only three! I am dead beat.

Huq ducks out the grand final — her crown is taken by a first-timer, one Suzanne Doyle of Stratford. Champion of the world? Champion of Soho, at least. Next stop: Machu Picchu.

You know those dreams, where you find yourself in a familiar house only the house contains more rooms than you ever thought, and rooms come off rooms, passages open out into chambers and before you know it you have strayed somewhere else altogether?

London can be like this. Last week, I walked though a bomb-proof door on Furnival Street in Holborn and took a lift 100 foot down to a vast subterranean world that few Londoners ever suspected existed.

These are the Kingsway Tunnels, a secret underground bunker over a mile long that present owners, BT, have just put up for sale. Built originally as the Chancery Lane public bomb shelter in the Blitz, the lair was taken over by MI6 until the end of the war, before the Public Record Office took residency and finally GPO (BT as it was then known) bought it up and extended the network of chambers and passages in 1956.

It became the Kingsway telephone exchange, the most secure in Britain. Broken circuit boards and a framed Factories Act of 1944 bears witness to it now - it's like a vision of a future that never was. Rumour has it that MI6 sealed it off, manned, for a fortnight during the Cuban Missile Crisis - but fact recalls that until the mid-Nineties some 150 telephone engineers worked here daily. There was a snooker hall, a canteen adorned with pictures of palm trees, a brown, tube-shaped bar and a tropical fish tank.

Still, it remained secret. The supervisor who led our tour claims those who built it were shipped in, spoke no English and had no idea where they were working - a precaution. Even now, displaying a level of secrecy that suggests the war never ended, he refuses to reveal exactly which street it lies under. An electrical diagram on the wall for some reason incorporates the old newspaper offices on Fleet Street. Was this place used for wire-tapping journalists? No one will say.

Of course, the temptation is to sneak off away from the press corps and explore the tunnels by myself - "Oi! Don‘t open that door!" I am told, though, whenever I slip away. Or is that a smoke screen, a red herring? How many more such places are there in the bowels of London.

Tar seeps through the walls. Central Line trains rumble past, unnervingly close. It will take any prospective buyer at least another £5 million to render the space suitable for commercial use: storing bullion, say.

I say the Punchdrunk theatre company should turn it into a living art installation. Or an eccentric billionaire sould perform weird fantasies down here. Or Dr Strangelove's vision for a post-nuclear society could be acted out!

Excuse me. Must be the lack of daylight.

King’s Place, the new concert hall complex in King’s Cross, is a place you feel virtuous simply for entering. All that spanking new oak, bright open space - it is the architectural equivalent of a bracing stroll through the Black Forest.

But what of the programme? At last week’s lavish opening ceremony, I was intrigued to see programmed a film by the Pet Shop Boys, exploring their associations with King’s Cross - what nature could they have, I wonder? But my eye was drawn by a regular series of events which go under the banner This Is Tuesday. This being Tuesday, This Is Tuesday is on tonight and features the avant-garde composer Huw Watkins.

I am pleased to find an event which makes a virture of its Tuesdayness. I feel a certain allegiance with Tuesday, it being the day I am permitted to muse on such matters, and yet, it is traditionally unloved.

If the week were a life-span, Monday would be childhood and Tuesday adolescence - pimply and unsure of itself, where every false move feels as if it will haunt you forever. Or at least until the end of the week - the retirement home of Saturday and Sunday's gentle death.

Tuesday often finds you at a disadvantage, too - if your Saturday night has been particularly large and spilled over into Sunday, it is not Monday - which can be rather jaunty - but Tuesday when shivering horror is apt to strike at the desk. Gone is Monday's fresh dawn; Tuesday means business.

If you find yourself in this state, use its serious demeanour to your advantage. You are much more likely to find a seat for an acclaimed production than on any other night. Many theatres, including my excellent local, the Arcola in Dalston, offer pay what you can pricing, making it a good time to do something worthy, even if you snooze through it.

But better still, defy it all and go out properly. Recently Wednesday and Thursday have made claims on Londoners' social diaries in this regard, but the case should be made for Tuesday. I always prefer the midweek atmosphere of a club to the sweaty, exploitative weekends. Those who do make it are more dedicated, and clubs are likely to book more experimental and interesting promoters - such as tonight's reputed iHEARTNiYi night at Punk in Soho (www.myspace.com/iheartniyi), or Galvanised - a leftfield noise event at the Oto café in Dalston (www.myspace.com/galvanisedfestival)

As the nights draw in, it is pleasing to take advantage of London's nightlife for cut price, without the crowds, with the thought that everyone else is at home watching Who Wants to Be a Millionaire: Nurses Special.

Do it properly and its leads logically on to Wednesday: the best day to pull a sickie.

What could be more salubrious than taking your mother-in-law to a matinée? As it turned out, the play, Six Characters in Search of an Author, featured a fair dose of incest and rape, but she’s an open-minded gal. Besides, this turned out to be immaterial. I had come unstuck before I even entered the theatre.

Our meeting was set for 2.30pm on Shaftesbury Avenue. I arrived at Piccadilly Circus at 2.15pm, but in my haste to be early, I had not thought about lunch - and did not fancy Pirandello on an empty stomach.

Not long ago, I would have nipped to the New Piccadilly café on Denman Street for a bacon butty. But it’s gone. And, moping hungrily towards the theatre, I could think of nowhere in this tourist hellhole that would tally with the amount of cash I had in my pocket. And then I looked up and saw McDonald’s.

Now I haven’t been to McDonald’s for years, thanks to the revelations of Fast Food Nation and, it’s true, the rise of the West Cornwall Pasty Company. But times are hard. And right now £1.19 for a double cheeseburger sounded like a deal.

I decided to scoff the thing as quickly as poss, standing upright, on the premises, then eat a lot of gum and scoot to the theatre. Nobody, except other people who eat in McDonald’s, would see me here, so my reputation would be safe. I drew breath and lost myself in the business of eating. Until:

"Richard?" As if in a bad dream, my mother-in-law was standing in front of me. "We thought it was you!"

[ITAL]We?[/ITAL]I wiped about of ketchup off my chin and looked to where she was pointing. She had been out with her friend and her friend’s daughter - and the daughter had, improbably, recognised me from across the road, through the window, from a photo! They waved, sceptically.

There was nothing I could do to regain my cool. I had to hold my breath as I kissed hellos, subtly pick bits of orange cheese from teeth, surreptitously slip the half eaten item into my pocket. I felt as if I’d been caught in a brothel.

There is much fashionable talk about the credit crunch - even a strain of competitive thrift emerging among the middle classes. But for every virtuous saving we might make, such as cycling to work, there are dubious ones we could also make, though our instinct is to turn our nose up. But if you are serious about thrift, shouldn’t snobbery go, along with champagne?

My mother-in-law and her friends had great fun with my embarassment. But the burger? Delicious, and filling, too.