Freshfields' City office was reportedly paint-balled, hit by custard pies and abseiled down by protesters, and City lawyers donned mufti to protect themselves from rioters campaigning against global capitalism in the Square Mile last Friday.
Linklaters, Lovell White Durrant, Dibb Lupton Alsop and Herbert Smith were among firms on the protesters' route who followed police guidelines by stepping up security, discarding their suits and leaving work early.
Sources have reported that Freshfields and Norton Rose were among firms which suffered at the hands of the campaigners.
A receptionist at Norton Rose says: "Our building is suffering extensive damage because of the protest."
A source says protesters appear to have targeted law firms in particular. Five activists are reported to have shaved the head of a besuited City type, while pinning him against Freshfields' wall.
The "carnival atmosphere" continued outside PricewaterhouseCoopers and KPMG, which were struck by nude protesters.
#A partner at the Foster Lane office of Scottish firm Maclay Murray & Spens says: "We're being besieged by open-toed-sandalled hippy vandals. We have armed our doorman, Bernard, with a shotgun."