Utilize the input text as a context reference, choose the right relationship between Tories 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 (ShareCast) - (ShareCast News) - David Cameron's government suffered its first defeat in the House of Commons on Monday night after eurosceptic Tories joined forces with opposition MPs to defy the prime minister on the rules surrounding an EU referendum.

Answer: headquarters_location