Utilize the input text as a context reference, choose the right relationship between Land Securities 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.

Although concerns over the slowing global economy present risks to the London property prices, underlying market trends suggest the outlook for Land Securities remains positive.

Answer: headquarters_location