London's West End has retained its position as the world's most expensive office location for the seventh consecutive year, according to a new report by property advisor DTZ. London (City) was ranked number 4. The 10th annual Global Office Occupancy Costs Survey is a guide to total occupancy costs across 131 business districts in 46 countries, divided into six regions. Locations are ranked on a workstation basis and costs are expressed in US Dollars.