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

The amount of office space being built in central London rose by 24 per cent in the six months to the end of March, a survey of construction activity by advisory firm Deloitte found earlier this year — the second-biggest increase in 20 years.

Answer: location_of_formation