In the autumn of 2012, London's Kindred politics are more volatile than they have been for centuries. The Inner Circle of the Camarilla is eying the city with mounting nervousness, but with its leadership outwardly stable, its night-to-night business seemingly well-run, and its Sect loyalties unequivocal, they've been unable to find an excuse to intervene in its affairs. (Although they're surreptitiously looking very hard for one).
Mithras, a fourth-generation Methuselah whose personal power rendered him almost unchallengeable, ruled the city for centuries. He seemed as immovable as a mountain, but the German incendiary that destroyed his haven in 1941 finally felled the ancient Titan. His Seneschal, "Queen" Anne Bowesley, became Prince following his presumed demise.
In reality, Mithras had merely been forced into torpor. He revived in the 1990s, but his plans to retake the throne hadn't progressed very far before he was grievously wounded by a pack of Lupines and Diablerized by an Assamite antitribu named Monty Coven.
Coven soon found that he had, almost literally, bitten off more than he could chew. Mithras' mind and soul overwhelmed him, virtually erasing his own personality. Within a year of the diablerie, Mithras was once again plotting to regain Praxis, this time using his would-be murderer's sect-mates as his pawns.
Unfortunately for the ancient, a small part of Coven's consciousness had survived, compromising Mithras cold-blooded tactical genius with its impatience and short-termism. In 2004, "Coven" led a group of Sabbat Crusaders and Camarilla malcontents in a lightning raid intended to destroy Lady Anne and her Primogen, but the plan of attack hadn't properly accounted for the strength of Lady Anne's defences. She was driven into torpor during the battle, but so was Mithras/Coven, and the insurrectionists were almost completely wiped out. . The bodies of Anne and Mithras/Coven vanished in the aftermath of the battle; nobody in London has any knowledge of their current whereabouts (that they will admit to, at least).
Knowing that a power vacuum in a city as large and important as London would force the Camarilla to intervene, London's surviving elders moved with frantic haste to restore order. Queen Anne had had no designated successor, and had, in fact, been prone to sitting heavily on anyone presuming to look too much like one. The elders spent a week in frantic political horse-trading, all the while looking over their shoulders for the expected arrival of a Justicar or his Archons.
The Prince who eventually emerged, Lisa-Beth Whitby, was a surprise compromise candidate. A mere three and a half centuries old, she was relatively young for a European elder, and her Malkavian blood didn't do much for anyone's confidence, but she a political shark of the first order, a respected Harpy and Elysium power-broker. Moreover, she was a veteran of several campaigns against the Sabbat, including a viciously thorough pogrom in 1848 that had left her injured and in torpor for several decades. A full-scale witch-hunt against the Sabbat was under way in the wake of Coven's assault, and she was a logical choice to lead it.
Nonetheless, her position is far from secure. Mithras possessed immense personal power, and Anne Bowesley enormous political power. She has neither. Under her rule, several competing factions have emerged, whose rivalries are barely restrained by the need to preserve the Masquerade and avoid a Camarilla power-grab.
The New Guard are those Kindred who have benefited personally from the change of regime. They consist of the Prince herself, the Sheriff, the majority of the Primogen, and a plurality of ancillae and neonates who found Anne's rule too heavy-handed and restrictive. Their grip on the levers of power is secure for now, but primarily thanks to the weakness, division or indifference of their opponents.
The Old Guard are their mirror image. This faction is made up of the childer, supporters, flunkies, and assorted hangers-on of Lady Anne and the members of her Primogen who were destroyed in Coven's attack. They lost most of their privileges and influence when the New Guard took over, but they don't have the strength to assert themselves without help.
The Camarilla is uneasy at the thought of a major European city under the command of an inexperienced Malkavian Prince and an untried Primogen, and they're monitoring the situation closely. The Camarilla Watchers are a group of elders and ancillae sent to London by the Inner Circle and Justicars, ostensibly to render aid and assistance to the new regime. Their real purpose, as everyone knows, is to keep a beady eye on things and call in the Justicars if things go to hell. The Old Guard lobby the Camarilla Watchers for regime change as frequently as they dare; the New Guard regard them as something close to the embassy of a hostile foreign power. The Watchers, for their part, are somewhat irritated by both. They were selected for their role precisely because they're not known for pushing their own agendas. Their job is to keep the city running smoothly, not screw things up; they'd prefer to see an end to the factional infighting, and they'd be just as happy to see the current Prince stay in power as replace her - provided that she can prove herself up to the job.
The Merchant Princes are also irritated by the factional infighting. As their name implies, their primary interest in London is its status as the world's premier financial center; they don't really care who holds the Princedom, as long as whoever it is keeps things stable and above all, profitable. Largely apolitical, they represent a "swing vote" that none of the other factions can afford to ignore; most of them are old and powerful, and all of them are very rich.
The Huddled Masses aren't really a faction as such; the term was coined by an Elysium Harpy as a form of mockery. In the wake of the Sabbat attack on the Primogen, London has become a very unwelcoming city, not just for the Sabbat but for any non-Camarilla Kindred. The "Huddled Masses" is a catch-all term for the few remaining Anarchs and independent clan members who managed to retain their positions in the wake of the Camarilla crackdown. They have, to some extent, been forced to co-operate with each other for want of any other allies, but their agendas are too diverse and mutually incompatible for them to achieve any real unity.