We walk down a shady alleyway between two 1950s houses and down a path littered with beer cans. On our left, an electricity substation gives off a happy low hum, as if pleased to be in use. We fiddle around removing the huge padlock from the gate, and then, finally, we are in.
Through this gate there is a surprising sight: a huge open space behind the houses. Apple trees and fallen mulberries amid a meadow of long pale grass are the few signs that this is the Rose Lane allotment site. I've been trying to get to see these neglected allotments since last winter, as they were the only plots in my borough with less than a four-year waiting list. In fact, I've been waiting so long I had begun to think they might just be a figment of someone's imagination. But my local allotment officer (described to me by his tenants variously as "very helpful", "a star" and "totally overworked") has almost 40 sites to manage. Though he kept talking about the planned rejuvenation of this one, nothing happened until a ball of energy named Dawn took over as a volunteer.
Dawn and I walk around the allotments, smelling the ripe tomatoes on one of the few plots still being cultivated. I actually get to choose which piece of earth I want: I sign some forms sitting on the grass next to Dawn's strawberries, she explains the rules to me, and I pay 2 for a copy of the key. And that's it. Plot number five is now mine - a piece of real estate, Dawn and I laugh, that would be worth hundreds of thousands of pounds if you could build on it, all mine for 36 a year. Hidden away - a tiny pastoral realm. So here we are in urban London, yearning for the pastoral. Later that day, travelling east across the entire sprawl to Bethnal Green, I found the flashes of green between houses more fascinating than ever; tantalising hints of the city's secret open spaces.
I went to Bethnal Green to see the prize-winning artist Justin Coombes's latest exhibition. The relationship between the city and nature is his starting point. His dramatically lit, large-scale photographs, remind me of Gregory Crewdson, though they are far more innocent. Somehow, hearing Coombes talk about his work, this doesn't surprise me, as he evokes his Devon childhood and politely evades questions about anything too personal, in a soft voice tinged with the West Country.
"I wanted to try to recreate memories from my childhood, finding sites around London, and using long exposures and images I had taken from home." So a sycamore tree at night, flooded with light, has a transparency of Coombes' much-loved childhood sycamore projected on to it. Several of the most striking pieces are images of allotments, where Coombes followed the impulse to recreate his mother's garden. Tower blocks and a flapping scarecrow add to a sense of mysterious charm and melancholy.
It's the performance pieces which Coombes and others bring to the opening night which most make me ponder the question of the countryside in the city - Coombes speaks about Romanian cities he visited as a child, where he saw high-rise buildings surrounded by vegetable gardens. His friend Adriana Salazar performs a poem about the refuge provided by gardens in cities. One line stays ringing in my head: "A point of exit, within."
The next day I return to my new allotment with a garden fork, a packet of radish seed, and a determination to start growing something to make my mark. After an hour in the sun with the gentle noises of Saturday floating over from nearby gardens, I feel fixed. Away from the house, I can't have a cup of tea (mental note: bring a flask) but I also can't get sucked into house problems or phone calls. I can't believe that after all that waiting I finally possess this little plot of land, surrounded by trees and totally peaceful. Leaving, I relock the padlock with a sense of overwhelming satisfaction.
'Urban Pastoral' is at Paradise Row, London E2, until 30 September,Wednesday to Sunday, noon-6pm; tel: 020 7613 3311