The Londons that could've been

The BBC has an article by Jonathan Glancey about the Londons that never were:

In the year 60 or 61, the fledgling Roman city of London was set on fire and razed to the ground by Boudicca, the flame-haired queen of the Iceni. Sixty years later, the city was ravaged by fire and rebuilt once again.
This time, Londinium, as the Romans called it, was a planned city, with a gridded street layout. Two major roads running east to west led to a large forum, basilica, amphitheater, and temple of Jupiter. The city’s life was focused on these major public buildings and spaces as well as on its busy docks and traffic-laden bridge over the Thames, where London Bridge stands today.
Intriguingly, the plan of Roman London proves to be not so very different from that of Sir Christopher Wren’s, drawn up after yet another blaze: the Great Fire of 1666.
This, though, was not entirely a coincidence. Wren would have known little of Londinium, but the new London he imagined was laid out geometrically on the same square mile that Londinium occupied, an area referred to in Wren’s time, and ours, as the City of London, inspired by what he knew of Classical, and thus Roman, architecture and town planning.
In Wren’s plan, two diagonal boulevards cut across a grid of handsome, stone-fronted streets leading to and from a grand new Royal Exchange and an imposing new St. Paul’s Cathedral. These two buildings would have been the equivalent of the Roman basilica and temple of their day.
It was not to be. Instead, the City was rebuilt in a rush, along the old maze of medieval streets. London was in a hurry to get back to work, and plans for an ideal Roman-style, grid-plan city adorned with spacious piazzas were seen as little more than costly and time-consuming architectural pipe dreams.
As a result, Wren’s plan had no immediate effect on London, but it was dusted off and studied several times over the years. Wren’s embankment along the Thames came to pass in the nineteenth century, for example, further west along the river. Wren’s influence can be seen, too, in plans drawn up in the 1940s to rebuild post-war London.
The four rival designs presented to the City and Charles II in 1666 (now on show at the Royal Institute of British Architects exhibition, Creation from Catastrophe: How Architects Rebuild Communities, weren’t quite as lucky.
Taken together, the considered geometry of the Restoration plans is in vivid contrast to today’s largely unplanned modern London. The proposals, by Christopher Wren, Robert Hooke, John Evelyn, Richard Newcourt, and Captain Valentine Knight, speak of a Restoration-era longing for a capital city that, escaping from its burned-out medieval past, might rival Rome.
Those by writer and landscape gardener John Evelyn and by the scientist Robert Hooke are essentially more modest, less accomplished versions of Wren’s. What they depict is a noble commercial city where, despite the scale of the site allotted to the new St. Paul’s Cathedral, God appears to play second fiddle to Mammon, as wealth was then, as now, the city’s ruling deity.
Richard Newcourt’s plan is very different. Theocratic in spirit, it places God and the Church first. The noted cartographer and architectural draughtsman proposed a chessboard of 64 squares, each with a church at its core. His relentless ecclesiastical grid was to have been broken only to admit the all-important Royal Exchange and St. Paul’s, the biggest church of all. While today’s City has more than fifty churches, they are potted about streets, courts, passages and alleys like pieces of some playful architectural puzzle.
Newcourt’s plan may have proved antithetical to the commercial spirit of London. But it did influence William Penn, the English Quaker who founded the city of Philadelphia in 1682. Penn asked Surveyor General Thomas Holme to draw up a gridiron plan filled with houses and gardens rather than temples of religion and commerce. This grid plan was to spread from Philadelphia across the United States.
Captain Knight, a Royalist officer during the English Civil War, drew up a fifth plan for London rooted in the City’s commerce. St. Paul’s aside, few churches are shown in Knight’s drawing. What he proposed was yet another grid plan, divided by two east-west boulevards. They would cross eight north-south streets that were sub-divided into narrow lanes lined with tenements.
If Knight’s plan lacked Renaissance-style flair and panache, what it did offer was a broad canal coursing around the revived City.
Knight calculated that taxes earned from canal traffic would earn the Crown £233,517 a year in taxes, a sum equivalent to more than £32 million today, and one which could have paid for the new St. Paul’s Cathedral in less than five years. Charles II, however, was not amused. How dare Knight suggest that the King might benefit so richly from a “public calamity”. He meant the Great Fire, of course. Instead of praise, Knight was thrown into prison.
Except in elegant patches, London has never been much of a planned city. Even its handsome Georgian squares seem placed on the map at random. London is a bricolage, a jigsaw puzzle, sometimes a miasma of streets and buildings in any number of layouts and styles. 

The City of London today, with St. Paul’s in the foreground (photo), is a mishmash of architectural styles and winding streets.
At its heart, London has always been a money-making-machine, and commerce, rather than culture, has determined its design. From the eighteenth century, London grew rapidly: although attempts were made to build sequences of interlinked garden squares to beautify the city as it expanded west, most commercial development was built wherever a plot of land became available. There was neither the time nor the will for more elegant, long-term plans. As for the City of London itself, buildings were and are demolished and replaced on cramped medieval sites, not so much to preserve the pattern of old streets, but because long-term plans to do anything else continue to be a costly nuisance.
This randomness maps and mirrors London’s seething and unpredictable energy. Its often-uncertain streetscape reflects a sense of perpetual movement, one very different from that of a composed, geometric classical city. Had Wren and other architects managed to convince the City to adopt an ideal shape and pattern, it would have seemed elegantly chaste, even straightjacketed: a city held in a tight corset, unable to expand at will.
The Great Fire would not be London’s last chance to be planned under one grand design. Another opportunity came about when London was ablaze yet again, this time during the Blitz. In the course of the Second World War, more than fifty thousand homes in inner London were destroyed, and more than two million damaged. This was also the era of the professional modern planner, bent on streamlining London with fast new motor roads, towering blocks of efficient flats, flows of purposeful pedestrians separated from unheeding traffic, and spacious public squares faced with imposing public buildings.
But except for here and there, such comprehensive plans amounted to little. Like Wren’s and Hook’s, Evelyn’s, Newcourt’s, and Knight’s, these wartime and post-war plans, borne of fire, are the stuff of archives, histories, and exhibitions today. London has always been too busy to bother with grand plans, and perhaps, Great Fires aside, this has been for the best.

Rico says that Philly may owe Wren for its grid, and New York City may do more banking and commerce, but Paris is still prettier than all of them: