Possible Clues:

• London insurance association
• Famous London corporation of underwriters (5'1)
• Famous corporation of underwriters in London
• Famed London insurers
• Company that insured Marlene Dietrich's legs
• Insurer at One Lime Street, London
• List issuer, sly old crook
• British insurance giant
• London-based insurance company
• London insurer since 1688