Those controlling traffic lights are grey and upright. Then there are grey or green boxes about the size and shape of ... nothing I can think of. This camouflage-green one is typical: about five feet long, four feet high and one foot wide. It's set back on the pavement between a bus stop and an advertising hoarding. And I wouldn't have noticed it under normal circumstances. Moving between the cafe's tables, I make my way round the perimeter of both the cafe and the Isle of Dogs. The grey and the green boxes crop up in all sorts of conjunctions. I cross the cafe in order to go round again ... Joanna points out that I could go outside and see the real thing. We've finished our coffee so, fine, let's do that.
Within 20 yards of the arts centre is a terrace of houses, two of which have olive-green boxes on the pavement in front of them. Sheet aluminium; pitched roofs; slats for ventilation at both front and back, top and bottom; a circular steel locking mechanism for which I don't have the key. But if I did, I'd open the two doors from the centre of the unit's front. And then what? It's a BT junction box, Joanna tells me. Some are underground. But overground units allow engineers easier access and don't lead to problems with damp. I nod thoughtfully.
The next green box has been built into a boundary wall. And there are brick pillars mounted with concrete tops flanking either side. I don't know why the bloke building the wall would do that. Unless he was intent on drawing people's attention to the reality of today's urban environment.
The next jungle-green box is made of cast iron. "GPO" is stamped into it. I ever so vaguely remember that the telephone system used to be run by the Post Office. When these new houses were put up, pavement and boundary wall made space-wasting efforts to accommodate this old junction box. I'm beginning to think it's only me who hasn't noticed these things before and given them due import.
Here is a pair of units, side by side. They're of slightly different design. The first is the size and style we've seen until now. The other is perhaps a more recent model. It's flat-topped; there are several key points because there are several doors; and there are only air vents at the back, and then just on one side. One of Tony Peakall's photos was of a box like this. And on top was a Pepsi can and a plastic cup. I put my elbows on the unit and let it take some of the weight off my feet. Joanna points out that the square manhole covers in front of both boxes incorporate the letters CATV. Carlton Television? "Cable TV!" I announce, suddenly on firm ground.
The small box is for normal channels. This big new box is for porn. (Though with such hot stuff passing through it, the design should incorporate more of those dinky ventilation slats rather than fewer). So, when the present government - on grounds of community welfare - decides against softcore being cabled in to homes and businesses, then the Communications Man just opens this unit and disconnects the lines. And when a future government decides that uncensored sex between adults is all right after all, it's just as simple for the Engineer to reconnect ...
Out of the corner of my eye I catch sight of a post box. The bright red pillar and unambiguous black slot are altogether too much. I go weak at the knees ...
Time passes. A man paints a line, a dot and a number 5 on the paving stones close to where I lie. "Is this pavement art?" I ask. He shrugs. He tells me that a new unit will be going up in accordance with the marks he's just made.
Tony Peakall, 'Life Belt': St Paul's Arts Centre, E14 (0171 515 7799), to 30 September.
'Personal Delivery', Duncan McLaren's book on contemporary art, is out now from Quartet (pounds 12).