Heather Mills McCartney was left limping in agony after allegedly having her false leg knocked off by one of Jennifer Lopez's bodyguards during a fur protest at J. Lo's fashion headquarters.The injury occurred as Heather, who lost her real leg in a motorbike accident in 1993, stormed into the New York office of the Latin diva's fashion label, Sweetface, which uses fur in its clothing range.The former model, married to Beatles legend Sir Paul McCartney, was attempting to show Lopez a video showing racoons being skinned alive in China.During the protest, Heather clashed with the star's security guards and as they tried to move her out of the building her prosthetic leg reportedly twisted and came loose, leaving Heather writhing in agony.As the fracas erupted, J Lo's security team were overheard shouting at the attractive blonde, "Get out of here! You have no authority to be here! You are not invited"After losing her false limb, Heather - who was joined by animal rights campaigners from PETA for her protest - begged security to allow her to use a bathroom so she could re-attach her leg but they refused. Photographer Richard Corkery, who witnessed the incident, said: "She was obviously in pain but she found a fire exit to hide in and re-adjust her leg I saw her limp away from the offices as JLo's men were still shouting at her to get out"