In the matter of green open spaces, as with most of London's amenities, it's the rich wot gets the manicured pleasure grounds, while the poor make do with scruffy scrubland dotted with turds. Those lucky enough to live within strolling distance of Hyde Park, Regent's Park and Kensington Gardens can escape from their luxury duplexes and sit on clean seats to gaze at lovingly tended flowerbeds. Just a few miles out, on the turbulent brink of civilised living, those park benches that have not been ripped up are etched with graffiti, while the soft scent of the flowerbeds competes with the harsher odour of urine.
Guidebooks to London often boast that it is one of the greenest cities in the world. Most tourists - seldom straying beyond the glittering centre - might well find that to be true. Only those adventurous souls who make their way to the bleak expanses of Wormwood Scrubs or Peckham Rye will discover that not everything in the garden is quite so lovely.
Will the new mayor and London authority do anything about this blatant inequality? I have not detected it on any of the candidates' agendas. The common excuse for the poor state of the capital's municipal parks is the assault by successive governments on local authority spending. Maintenance and horticulture have been farmed out to private contractors, while the valued council apprentice schemes - where many professional gardeners received their initial training - have been scrapped. Once-elegant Victorian bandstands stand forlorn, decaying and unused.
Lambeth Council has just allotted a pathetic £20,000 to see what can be done to revive down-at-heel Clapham Common for the benefit of the man and woman on the fabled omnibus. The sum needed to do the work properly would be beyond the council's means, short of private sponsorship or Lottery money - that modern universal panacea. The better funded royal parks in central London, catering to the carriage trade, have faced less damaging cutbacks. Even the foxes, which used to restrict themselves to the capital's outer rim, now prefer the more palpable delights of the Westminster parks, and can be seen taking the air in Downing Street.
There is nothing particularly modern about this class distinction. The first book about green London, The City Gardener, was written in 1722 by Thomas Fairchild, an innovative Hoxton nurseryman, who made horticultural history as the creator of the first man-made hybrid from two different sorts of flower. In his book he sang the praises of the royal St James's Park, as possessing "an agreeable beauty . . . which is wanting in many country places". Then he added waspishly: "The quantity of ground, which now lies in a manner waste in Moorfields, might undoubtedly be made very agreeable, was it to be adorned after the same manner, and be as delightful to the citizens as St James's Park is to the courtiers."
Alas, it never happened, as Fairchild probably knew it would not. Moorfields is today the built-up area between Moorgate and Liverpool Street Station: then, as he would have observed on his frequent walks between Hoxton and the City, it was the Georgian equivalent of Clapham Common, a disorderly spot where it would be imprudent to accept dinner invitations from strangers.
Unlike courtiers, citizens have had to battle for their precious open spaces. These struggles are vividly described by the combative Bob Gilbert in The Green London Way, one of the best guidebooks for London walkers, published by Lawrence & Wishart in 1991. Gilbert devised a route around the capital linking the open spaces on its perimeter, starting and ending at Finsbury Park and taking in Woolwich, Crystal Palace, Balham, Richmond, Harrow and Hampstead on the way. For him, the campaigners for access to common lands were heroes: "In Plumstead and in Forest Hill people marched in their thousands to save their commons. In Richmond it was a lone local brewer who took on the courts and the monarchy to re- establish the right of access to the park. In Hampstead 15 different parliamentary bills had to be defeated in the struggle to preserve the heath. In Streatham local people turned out in secret to tear down gates and fences on the common as fast as the Lord of the Manor could put them up."
What a shame, then, that so many of these parks are in such a grim and grimy state. There are a few exceptions, bright spots amid the threatening gloom. The hill garden on Hampstead Heath's extension, created by the Lever soap family when they lived in the adjacent big house, has been well restored. The rookery at the south end of Streatham Common, also once a private garden, is kept at an acceptable standard. The rhododendrons in Dulwich Park continue to be a dazzling precursor of summer. But beyond these isolated gems, local authorities can do little more than watch the remorseless decline of open spaces, which they cannot afford to keep up to scratch. They see it as something of a triumph just to keep the loos open.
It is true that in recent years some new recreational areas have been opened up. The Thames path, which for years ran no farther east than Putney, now extends right through the capital, offering alluring views of the river banks and the much cleaner water that flows between them. The towpaths of many canals have been transformed into footpaths, although some of these, too, suffer from lack of adequate maintenance.
London's 19th-century cemeteries provide some of the best rustic walks and havens for wildlife: the mid-Victorian part of Highgate is now accessible again, as well as the newer bit across the road that accommodates Karl Marx. Cemeteries such as those at Kensal Green, Nunhead, West Norwood and Abney Park (described by Gilbert as "delightfully overgrown") are charming and atmospheric. Here the sense of decay appropriately enhances our appreciation of man's mortality.
The distinction that Fairchild drew between public spaces for courtiers and those for citizens does not derive only from the level of resources available to create and maintain them. There is, too, a conflict about the uses to which parks should be put. Recreation means different things to different people. In the royal parks the main activity has traditionally been riding and carriage-driving, attractive and genteel diversions confined to those who can afford a horse. The animals and their riders make a picturesque adornment to the bucolic scene, and one that can, moreover, be confined to the parks' perimeters, leaving the centre free for fragrant flowerbeds and ornamental lakes.
Just what activities should be permitted in municipal parks is frequently a source of contention. Sadly bowls, undertaken in slow motion by imperturbable men and women in smart white uniforms, seems to be going out of style, and has vanished from my local park at Vauxhall. The encroachment of tennis courts and soccer pitches, though they clearly fulfil a local demand, detracts from the contemplative mood that many of us crave when we choose to commune with nature. Cyclists, too, believe they have an inalienable right to race along park pathways, often oblivious to the comfort and safety of pedestrians.
Fairchild, perhaps London's first true friend of the earth as well as of the common citizen, was keen to see less artifice in the capital's public spaces - a precursor of Capability Brown a few decades later: "The plain way of laying out squares in grass plats and gravel walks does not sufficiently give our thoughts an opportunity of country amusements," he wrote. "I think some sort of wilderness-work will do much better."
He argued that planting groups of trees instead of flowers would provide a haven for birds as well as a delight to the eye, and would block out the sight of the surrounding built-up areas.
He certainly would not have approved of tennis courts, running tracks and cycle paths. Nor of the bleak concrete enclosure, just off the Hackney Road near Shoreditch church, where his tombstone may still be seen.
The Ingenious Mr Fairchild, Michael Leapman's biography of London's pioneer environmentalist, will be published by Headline in May