Utilize the input text as a context reference, choose the right relationship between G4S and LONDON from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

LONDON (Reuters) - Britain's G4S Plc (GFS.L) said it won a $187 million contract to provide security services to a gas plant in Iraq, while in Afghanistan, it renewed a contract to provide protection to the British government.

Answer: headquarters_location