Do you ever get the strange feeling you're being watched? You are

Tom and I borrowed our friend's Mini to drive to Canary Wharf. We had been lent it to collect for him a consignment of lighting fittings ordered from John Lewis, which he had no time to collect. This was kind of us.

Motivated thus by charity we drove off towards the smart new shopping centre within the Docklands development on the Isle of Dogs in east London. We must have looked an odd pair. Tom, who (it is fair to say) does not over-dress, is twenty-something and resembles a younger Hugh Grant dragged through a hedge. My habit is to throw on whatever assortment of clothes lie on my bedroom floor. I had not shaved for a few days, and had mislaid my hair comb. Still, the security man let us past the barrier where they stop you and ask your business in Docklands. Tom said 'John Lewis' (one does hope al-Qa'eda never tumble to this password) and the barrier lifted.

Much of Canary Wharf, including the car parking, is subterranean and you are soon in a strange, windowless, concrete-lined world illuminated by flat white fluorescent lighting: a world in which there is no north and south, the signs — '131', 'Cabot', 'Service', 'Red Floor' — mean nothing, the painted directional arrows on the road beneath you always seem to be pointing against you, and every exit or entrance looks like every other. We drove on and looked for a parking bay.

Everywhere there were cars. All the bays were full. Nowhere were there people. We were alone and disoriented in a full-up void, a cavernous, blindingly lit, anonymous electrical hum. We lost track of which aisles and galleries we had already driven down.

All at once, on the Red Floor, I spotted four big bays, top-surfaced unlike the others in a livid green. Three were empty. A sign said 'Parent & Baby Parking Only'.

Tom and I exchanged glances. 'Do you judge me sufficiently infantile?' Tom asked. 'Do I look responsible enough to be your dad?' I replied. We drove in. Locking the Mini, we darted hasty and sheepish glances all about us. But there was nobody.

Do not judge us harshly, reader: we knew we would not be away long; we were doing a friend a good turn; and a choice of a couple of unoccupied bays remained at the disposal of any parent and baby who should happen this way. 'As I have never seen a baby at Canary Wharf,' I remarked to Tom, 'it would be unlucky if two turned up at once at 11 o'clock on a Monday morning.'

We traipsed off to become lost in the bewildering system of lifts and tunnels beneath the differently named blocks of shops and offices which towered above us, trying to remember features of the landscape (a shop selling cards and pink cardboard hearts; a mid-precinct coffee area where sad, smart people sit alone eating sandwiches) in case we should ever try to retrace our steps. At last we found John Lewis, which is above Waitrose. Surprisingly the shop assistant agreed to release to us our friend's lighting fittings, and then we became lost again, searching for the John Lewis collection and loading bay. Finally, bearing cardboard boxes, we found the Red Floor again, and there was the Mini.

But what was this? On the windscreen a big white notice. 'You read it, Dad,' said Tom, then (loudly) 'I can't read yet because I'm a baby.' I read out loud:

PARKING WARNING NOTICE

In order to accommodate the parking requirements of all users of the car park, Canary Wharf Management have provided 'Parent & Baby' bays specifically for the use of parents with young children shopping in the retail area. We have recorded your registration number and will continue to monitor these bays. . . . Please call the Car Park Office (0207 418 2752) if you wish to discuss the foregoing. . . .

There was nobody in sight. Tom and I looked at each other in horror. We had been observed — perhaps were even now being observed — but by whom? 'Maybe an attendant came round while we were shopping,' I said. 'Don't be silly,' said Tom. 'How would he have known a parent and baby had not parked this car and departed? You don't have to have a baby-seat or one of those "baby on board" stickers to carry a baby, you know, it's not compulsory. Obviously we have been continuously moni

tored by a hidden CCTV camera. Someone in a control room somewhere saw us get out and realised neither of us was a baby.'

'But from this day forward this car will for ever be under a cloud,' I said. 'Its owner's name may appear on a register of Abusers of the Parent & Baby regulations. This could seriously prejudice him in some future legal action. His character is stained.'

We discussed what, if any, action to take. Tom suggested returning to the shops and buying a big doll, swaddling it comprehensively and carrying it tenderly back to the car with its face buried in his chest — then telephoning the special number to get the Mini taken off the list.

'Or,' I said, 'we could say we did arrive without a baby, and not unreasonably, because we came to Canary Wharf to take delivery of a baby; but now we've learnt that the baby is not ready for collection.'

'Collection from where?'

'One of those new creches Gordon Brown is promising to fund.'

'They'll ask you where this crèche is located, and check you have a baby there.'

'Let's just get the hell out of here. Do you think they're watching us? Listening to us?'

Both of us felt suddenly cowed by the imagined presence of a seeing eye and perhaps a hearing ear concealed somewhere near us. Guilt was written across our faces as we ducked into the Mini and drove off, babyless. At the pay-barrier we became convinced we were about to be apprehended, and sat there grinning foolishly as the unsmiling attendant took our John Lewis parking token. But whatever he knew, he said nothing. The sense of relief as the boom was raised and we drove through towards the daylight was palpable. 'Slow down,' said Tom. Don't get flashed by one of those speed cameras they have everywhere now.'

As we walked through the door into my flat and locked it behind us, I felt the sense of surveillance lifting which Orwell's Winston Smith must have known when at last he knew Big Brother wasn't watching. Reader, the day is coming when we shall all have to proceed on the working assumption that, at all times and in all public places, we are being watched. Already I know that in subterranean parts of Canary Wharf I am a marked man,

Matthew Parris is a political columnist of the Times.