LONDON (Reuters) - They work under the cover of night, armed with seed bombs, chemical weapons and pitchforks. Their tactics are anarchistic, their attitude revolutionary. Their aim: to beautify.
An army of self-styled Guerrilla Gardeners is growing across the world, fighting to transform urban wastelands into horticultural havens. To document and encourage their victories, one of the movement's top generals has written a handbook.
"On Guerrilla Gardening," by Richard Reynolds, defines the activity as "the illicit cultivation of someone else's land."
"Our main enemies are neglect and scarcity of land," said Reynolds, a 30-year-old former advertising employee who wrote the book after his website guerrillagardening.org became a global focal point for would-be green-fingered activists.
"Land is a finite resource -- and yet areas like this are not being used. That seems crazy to me," Reynolds told Reuters.
"And if the authorities want to get in the way of that logic, then we will fight them -- but peacefully -- through showing them what we can achieve with plants."
As he spoke, Reynolds and several London-based troops were enthusiastically digging over soil in a rough patch of grass outside a tower block in the south east of the capital.
Defying darkness -- and risking arrest for criminal damage -- they continued their "attack" on the otherwise grim, grey surroundings, forking in a hefty load of compost and planting lavender and Paris daisies for a splash of color and scent.
Thousands of "troops" worldwide have now signed up to Reynolds' website -- each with their own troop number -- where they post reports and pictures of their battles, or "troop digs."
For those inspired to follow suit, his book outlines tips and advice on everything from the most suitable clothing and what kind of lighting and communication equipment to use, to how to carry out a "seed bombing" raid.
"Scattering seeds is the easiest way to guerrilla gardening," he writes. "You do not even have to stop moving to do it -- GG (Guerrilla Gardener) 830 Tony releases handfuls of Welsh poppy seeds while driving along the M60 motorway."
Reynolds says he was inspired to write the book after his first nocturnal gardening experience outside his own 1970s concrete tower block in London, when he discovered he was part of a largely secret but worldwide movement.
"I began because I moved to a tower block and had no garden, and yet all around me there were bits of land that nobody was looking after -- so I have made it into my own garden. But it's that one everyone shares and can get involved in," he said.
"I stepped out into the world to cultivate land wherever I liked. The mission was to fight the miserable public flowerbeds around my neighborhood."
The book charts what it says is a "revolutionary history" of a movement which has its roots in 1970s New York and has since inspired urban dwellers across the world to defy authorities and adopt and cherish neglected public spaces.
GG 3516 Greg, in Zurich in Switzerland, tells of Saturday-night sorties to beautify a traffic island in the city, while GG 158 Luc, in Montreal, Canada, documents a "pavement garden" he has been cultivating for four years.
GG 013 Julia, one of the movement's leading lights, posts pictures and descriptions of significant victories in Berlin, where the Rosa Rose garden in the east of the city has grown out of a vacant lot once covered in rubble and rubbish.
GG 1168 David, and GG Michael 1169, graphic designers in Tokyo, say their motivation was a passion for growing food.
According to Reynolds' book, they began in 2005 by "chucking pumpkin seeds into a vacant lot near David's home" in the city, and, encouraged by the pumpkins' progress, continued with a small guerrilla farm on waste ground in the Kamiyacho district.
"It's about living in an edible jungle," David, who now also grows broccoli and radishes land owned by Tokyo city authorities, says in the book. "Vegetables are best fresh, so I thought they should be grown locally."
Guerrilla Gardening is a crime in Britain -- digging up land you do not own is classed as committing criminal damage -- but Reynolds insists it is a victimless one and is clearly unfazed by encounters with police.
"Yes, by law this is criminal damage... but common sense would suggest it is quite the opposite," he said.
He described a recent night-time dig on a large roundabout in central London where dozens of police pulled up, and ordered him and fellow gardeners to down tools or face arrest.
"We reluctantly withdrew," he said, adding with a smile that they returned to finish the job an hour later when the coast was clear.
Reynolds has now largely given up his more mainstream work in advertising and devotes his time to writing about Guerrilla Gardening, maintaining his website and spreading the word.
And while he characterizes the activity as a battle and uses the language of war, he insists there are no losers.
"This a win-win war," he writes. "Take a public place of wasted opportunity and turn it into a garden. In time victory should be clear to everyone, and probably fragrant too."
Reporting by Kate Kelland; Editing by Sara Ledwith