Evidence suggests that more of the City of London’s office space lies vacant than first supposed - recent Investigative piece

A survey of the energy consumption of randomly selected mid-sized commercial offices in the City of London suggests that more are unoccupied than figures provided by real estate brokers.

Leading real estate agent Savills estimate that 7.4-9% of London’s financial centre has no tenants, while Avison, real estate advisors, put the figure as low as 5.4%.

Evidence based on the energy usage of buildings however, suggests that many properties under lease are empty. Their energy consumption figures are consistent with figures for vacant buildings with only essential functions running.

I conducted the study after walking around The City and noticed that it seemed emptier than headlines of low office vacancies and firms being stuck in their buildings from lack of options suggested.

I randomly sampled 200 mid-sized commercial offices within the Square Mile. I collated their publicly available energy usage, measured in kilowatt hours per square metre per year (kWh/m2 per year) and cross referenced it with registered leases.

A typical office building will consume 215 kWh/m2 according to the UK Government Energy Audit, while an empty office building, running essential functions like dehumidifying the air and keeping pipes from freezing, will use energy in the range of 60-100 kWh/m2.

The buildings that fell into this range comprised 12% of the sample. Rather than suggesting a statistical anomaly, the survey highlighted an interesting phenomenon within the class of apparently vacant buildings. 34% of the seemingly disused buildings had existing leases.

This points to a situation where tenants have retained leases on buildings that they are not using. This could suggest that the death of home working is not as final as supposed, nor that apparent scarcity of commercial real estate is as straightforward as it seems. Leaseholders have been contacted for comment.

With many of the leases having one or two years to run, it is possible that London could see a decrease in its office costs mirroring the fall of housing prices within the city and its periphery. Average property prices in the capital fell by 2.4% in 2025. Though, with robust demand for new office space and a shortage of new stock caused by a post-Brexit building slump, the data does not suggest that London will see a meaningful price correction.

However, this evidence forms an interesting counterpoint to real estate broker Knight Frank’s projection that vacancies for top London office space will fall to zero by 2028. It also presents potential solutions to companies unable to switch premises citing limited options. More than one-fifth of respondents to a CBRE survey of tenants in the UK and Europe last year said that there were “no suitable options” for relocation.

Perhaps this number could change if leases to reassign were included in their searches.