He means that walking isn't fun any more. Planners, architects, drivers and even walkers themselves nowadays seem to shrug their shoulders and chant the mantra "Streets are for cars". But Plowden wants us to have another think about that. It's why we're out cruising north London, deep into Kentish Town.
Plowden, 34, is the new director of the Pedestrians Association, which has just bagged about pounds 170,000 from a charitable trust to launch a fresh campaign to improve the pedestrian's lot. His organisation is currently running a national quest to find the best and worst streets in Britain, to make people think. From thinking, he says, comes sensitivity; from sensitivity comes political clout.
But more about that later. First things first. The bad news.
Did you know that more than 10 million people a year have accidents on dodgy pavements? That people are 10 times more likely to end up in hospital from a pavement fall than from a road traffic accident? That a fifth of our 152,000 miles of pavements are cracked and wobbly?
No wonder so many of us reach for the car-keys with wearily familiar implications for health, community and the environment. "If there was a malign dictator trying to discourage walking he would do exactly what we have done," Plowden says.
We are 100 yards into our walk, heading away from Kentish Town Tube up Leighton Road. There's a lorry parked slap across the pavement outside the Gloucester Arms. To get past, we must walk into the road.
But why should we have to? Plowden says we've all grown used to being pushed around by circumstance. It's partly due to odd laws. "In London, uniquely, it's illegal to park on the pavement," he says. "In the rest of the country it's illegal to drive on the pavement but not illegal to park. So police would have to bring proof that you had actually been seen driving on the pavement, which doesn't quite add up."
If we complained enough something would be done. But we don't. Walk on.
A few yards on at the junction of Charlton King's Road, and there's an Audi 80 up on the path, leaving a nine-inch gap to squeeze through. While Plowden is laughably doing that I watch a woman cross the road to avoid this little canyon. Just as she reaches the opposite side a van roars up behind, finds it can't get past some cars parked illegally on a yellow line, mounts the pavement in the woman's wake and cruises smoothly up until it's almost on her ... then it swerves back on to the Tarmac and away. The woman doesn't flinch but that only reinforces the horrible truth: we're all numbing down.
"Now this is pretty typical," says Plowden, pausing by a 50ft desert of dented, cracked and fissured paving stones. "That's been caused by parking, and someone who's blind or a little unsteady could easily trip on those ..."
As he is pointing this out (don't laugh) and being a teensy bit pedantic, an Evening Standard van backs out of a cul-de-sac, mounts the pavement and comes to within 18 inches of his back. Plowden doesn't notice because he's staring at his feet. I notice, but I don't bother to say anything.
It's not worth describing all the broken, badly uneven paving stones we continue to pass, though there are hundreds. Not that they don't matter. A recent report from Bristol revealed that the city council is paying pounds 1m a year in compensation to people injured by damaged footpaths - more than double the amount it spends on pavement repairs.
Plowden says: "The one thing about pedestrians is that they are flexible. The equivalent blockages on a road would draw lots of complaints because motorists believe that their journeys shouldn't be interrupted. Pedestrians say nothing."
Does Plowden have a car? No. Does he hate cars? No. "I don't hate drivers, either. The reasons people have become so reliant on driving is because that form of transport has been made relatively easy, convenient and cheap. This isn't a crusade against the car, it's a crusade for people who travel by other means to be given due weight."
For instance, when the Department of Transport assesses new road schemes a financial value is given to every potential minute saved in driving time. Yet if that road scorches through a town, forcing pedestrians to wait longer at crossings, or even walk a bit further, their lost time isn't noted at all. The funny thing is that all drivers are walkers at some time; but not all walkers are drivers. So which is potentially the biggest and most powerful group?
In the following hour we pass heaps of pavement problems - dogs' mess; advertising boards that squeeze us against walls and thick railings put up to keep pedestrians safe from speeding cars, yet inhabiting the pavement rather than the road, which seems a bit unfair.
Plowden stops at all of these and more to give a little speech, so that by the end of the afternoon he's quite hoarse. A critic would say he's seeking to create strife where none exists. Not so. His appeal has already bought a deluge of complaints from all over the country - more than 700 and rising. And someone who's been for a walk with Plowden would agree that it is probably time for trouble. Anyway, going back to that original point about his long-term intentions, Plowden is an old sly-boots. A public that flexes its muscles over basic pavement issues must in the end go on to ponder the whole role of the car in society. If motoring curbs are seen as a right rather than a resentful duty ... well, think about it.
Plowden is quite a revolutionary, really. Not pedestrian at all
Examples of Britain's best and worst pavements should be sent to: Pavement Survey, The Pedestrians Association, 126 Aldersgate Street, London EC1A 4JQ.Reuse content