UPDATE:  All Tremere have left the city, recalled to Vienna.
The Tremere:

The Tremere in London began the Chronicle in trouble and since then things have gotten worse.  Anne had Dominic’s predecessor quietly dispatched as he was in on her permanent removal of Mithras and he was stupid enough to use it as a bargaining tool against her.  The Tremere have suffered numerous setbacks ever since and are now effectively confined to one Chantry (the others have been destroyed, though Dominic does keep a Secret Chantry open for some reason)

Lord Dominic,
Tremere, Regent of the London Chantry, Lord of the South East of England, replacement to his predecessor and sire who died mysteriously during the troubles with Queen Anne. 
Lord Dominic is a strict leader, though one who is approved of by the higher ups in the Clan. 
He is a tall man whose head is shaved completely bald; he rarely leaves the confines of the Chantry in The Royal Courts and always wears ceremonial robes. 
Whilst a capable magus, he is a far better politician and has a ruthless streak a mile wide.  He also has control of the London Freemasons and so has a definite influence on the City of London police and the Courts.
Current Status: Dominic has revealed himself to care deeply about those in his charge, and his attempts to make headway to return the Tremere to their previous level of power.  Set against him have been spiritual attacks, assassinations, blatant politicking and, now, the Sabbat, though the Sabbat may be just the chance he needs…
Status 2, Clan Prestige 3

Jacob the Jackal
Tremere, Head of Chantry security.  The name is actually a term of respect and Jacob is a pretty good man (his Humanity is pretty high).  A few years ago he took pity on a dying police officer and embraced him to help guard the Chantry.  Jacob disapproves of the current hostilities and disapproves further of his new boss, but he has to follow orders, hasn’t he?
Jacob appears as an old, wiry man with a badly kept beard.  Despite his appearance, he is very strong, though he prefers to use his mind instead of raw brute strength. 
Current Status: DEAD, killed by Daniel Grey, possibly because he found out what Daniel Grey was and what he was up to.  Have also been indications that Grey was impersonating him at one point, or perhaps using Jacob in some way. 
Status 1, Clan Prestige 1

Jack Simmons
Childe of Jacob.  Embraced in `95, he serves as Jacob’s assistant.  Like Jacob, he would prefer if things were a lot simpler and there wasn’t a seemingly power hungry bastard in charge of the local Tremere. Not a very good magus, but has keen detective skills.
Jack is tall and gangly with a small box beard.  
Current Status: Jack is blood bound to Grey, who uses him as a mental puppet. Jack wants to die, but he has no way out as Grey keeps bringing him back from the edge.
Status 0

Lady Falchon
The emissary from Vienna, Falchon is from a powerful bloodline, it is known that her sire has a hand in the creation of the Camarilla.  For herself, she is eager to remove herself from the long shadow her sire casts. Her relationship with Lord Dominic is less than warm.
Current Status: Lady Falchon has been elevated to a position on the Primogen, no doubt as a bribe for assisstance from Vienna.

Status: 3, Clan Prestige 4

Lord Cawdor

The eldest Tremere in the city, Cawdor is a powerhouse of occult lore and understanding.  Distanced from the modern world, he rarely even steps from the Chantry beneath The Royal Courts, prefering to spend his nights in contemplation of whatever mystery currently holds his attention.  Recently, that mystery has been the jewel the Tremere came across...

Curremnt Status: Having been wounded in the retrieval attempt on the jewel by forces unknown, Cawdor is not too happy.  He is also sure that he now knows what the jewel is: It is the Jewel of Apollo, supposedly with the power to scry the future and bend the nature of reality, forged as was by the god from the very stuff of the Sun itself. 

Status: 1, Clan Prestige 4