We are told that time and space are merely aspects of the same thing, just narrow ways of looking at space-time, a four-dimensional continuum. And this makes sense and is all very well. The only problem is that you can't move to another moment in time in the same way that you can to another position in space. It's not as if you can hop on a bus to last week.

However sometimes  movement in space can simulate aspects of time travel. As long as you have somewhere to go that you haven't visited in years. Last month I went to Muswell Hill for the first time in around twenty years. This north London suburb was where I spent a large segment of my youth so in many ways stepping off the bus onto the Broadway was like stepping from the TARDIS.

Of course it helped that it was a dark evening and that I couldn't see quite how much things had changed.  There was just as much of the familiar shape of the landscape present to fool me into thinking I was back in the nineties or earlier, provided I ignored the lights of the vast towers of twenty-first century Central London on the horizon. Old London had been much more self restrained, with none of the science fiction aspirations of the modern city.

However, awareness of some of the changes that had taken place in the intervening years was unavoidable. The very act of noticing these changes started tweaking the time travel sensations of my visit so that it began to feel not as if I was in the past but in a dream.

One of the places that it is always possible to time travel is in dreams. The places we grow up have a tendency to hang around longer in the sleepscape and yet even there they begin to change, not as a result of corporate redevelopment but due to some strange mental renovation, they warp and twist until, whilst still recognisable, they become quite distinctive places in their own right, places which remain consistent from dream to dream.

But dreams are unreliable vehicles. If you really want to time travel the best means of conveyance remains the car (or public transport). It was while riding in the back of someone's car a couple of months ago that I realised there was a road that led back through my young adulthood to adolescence and childhood, different sections of which belonged to different eras.

This was the North Circular Road or - as I would later come to know it - the A406.

Looked at in itself it is an unremarkable and in places downright ugly twenty-five mile stretch of tarmac, but it's the associations that are important. It stretches right back to when my family returned to London (when I was three years old) and continues all the way into my early thirties. Even though in places the improvement works and redevelopments have made it unrecognisable, enough of the original structure remains to make many parts of the journey from Hanger Lane to the Crooked Billet all hauntingly familiar, with old memories, good and bad, bubbling up at unexpected moments.

Part of the familiarity stems from the aforementioned return to London and the visits to my grandparents in the Gloucestershire that used to occur at the time. These interminable (to a child) journeys would always start with a long section of A406 as the car built up speed orbiting London until reaching escape velocity at Hanger Lane and slingshotting out along Western Avenue towards Oxford. That arc of the A406 is the most familiar, the landmarks along the way laid down in my plastic child's brain at the same time as much of language and behaviour.

The initial subsection of that journey that was the most well known of all as we also travelled along it on an almost weekly basis on the way into Central London. A short stretch of The Great North Road took us past an evil building squatting at the centre of a field - at the time I was told it was the Latymer School but looking at it now on Google Earth it's clearly just a sports pavilion.

There was something about the horizontality of the windows and the way the roof overhung the building's face that convinced me it had bad things in mind.

This stretch of the road was always over quickly - even for a child - and then we got to the Great Cambridge Junction. Nowadays it's been superseded by an underpass but back then it was a huge roundabout and what stood out for me was the petrol station on one corner with a vertical sign spelling out its name (and now I can't remember whether it was Esso, Shell or something else) in neon letters set against square white panels like giant Scrabble tiles. This was also the point at which - if you knew where and when to look - you could see the Post Office Tower poking up about the infinite terraced houses which lined the North Circular at this point.

That was one of the weird things. A lot of this major trunk road was residential. I couldn't imagine what it must be like to open your front door onto that vast river of tarmac, juggernaut backwash buffeting your face with exhaust fumes and grit every few seconds.

Eventually (in modern terms after only five years but as a child it felt like forever) we moved westwards to East Finchley. Even though it didn't feel like it, this too was in close proximity to the A406 - at the other end of East End Road it lay like a canyon separating East Finchley from all of the other Finchleys. The safest way to cross was via the Northern Line. The journey to the grandparents remained more or less the same, just starting at a point slightly further along.

East Finchley also boasted the Great North Road or Falloden Way which approached the A406 from the south and then merged with it for five hundred meters in eight lanes of polluted tarmac which when I now look back I always imagine being viewed through a reddish grey haze. This was often where the traffic would grind to a standstill and I'd stare out the window at the central reservation. There, amongst the gravel, fag packets and sun bleached coke cans you would occasionally see other treasures - screws, mysterious fragments of machinery or pieces of shattered numberplate. Part of me wanted to get out and rescue this detritus, another part always wondered whether anyone else had ever looked at them and indeed whether I would ever see them again in my life. I imagined these inaccessible islands of tarmac and kerbstone sitting there timeless and changeless. They probably predated my birth and might very well outlive me...

(to be continued)

As a rule we tend to do a lot less crying as adults compared with when we were children.

It's understandable of course - when you are a child your brain is fresh and everything is far more extreme and world shaking. Even a turn of events such as your parents deciding that you're all going to eat lunch in a café not to your liking is enough to open the floodgates - I still recall how full of despair such events made me. It genuinely felt like the end of the world. Partly due to the aforementioned freshness of the brain but also I suspect due to the feeling of complete powerlessness in the face of your parents' authority.

As an adult however, crying sneaks up on you and squeezes out through half closed eyelids in the hope that no-one else will notice. It's an unwanted pressure behind the optic nerve and not something you want to do or indeed admit to doing.

It is also inspired by very different things, often things which have been specifically designed to provoke just such a response, the emotional manipulation of film and TV makers who build their fictional edifices for precisely this purpose in a similar way to the architects who - in the absence of actual gods - designed temples and churches so as to inspire awe and religious fervour in the attendees.

Crying as an adult is one thing but crying as a child was a very different process altogether. Crying as a child was always a journey through a storm, a hurricane of dark emotional turmoil. Sometimes you thought you'd never come out the other side. Your very being, your sense of self was being racked by mental tremors twisting you into new shapes. There was a very real danger that you would drown.

Then there was an interval.

You couldn't quite put your finger on it and the precise moment when you did come out the other side - the instant it started easing - was always inaccessible to you. All you knew was that suddenly there you were, adrift in a boat on a sea flat as a millpond. The sky was clear and infinite, and even though whatever had been bothering you was still there, you didn't feel quite as bad about it now.

You'd been through an exorcism, a fever. The back of your throat was sore and everything was suffused with a reddish brown atmosphere. Your breath would be interrupted by occasional involuntary sobbing-breaths tugging at your chest, aftershocks. At the time you couldn't clearly articulate it, but what had happened had undoubtedly done you good. The feeling was akin to the almost infinite calm you experienced in the back of your parents' car after an interminable motorway journey when they finally turned off and started driving more slowly along the A and B roads of the countryside. The nightmare of the everlasting grey tarmac 70mph roar was over for now.

Or maybe that was just me. Nevertheless the memory of the calm after the storm has stayed with me. The sound of the End of Motorway. Sometimes I hear it in songs or in the tone of someone's voice. It is the sensation that despite how bad everything might look right now, it will pass.

When things are at their worst I try and remember the experience of Having Been Crying. Of being driven up the slip road to the roundabout of calm. The roundabout is always there even though finding the right exit is sometimes tricky.