The number of cranes that pepper the skyline is a useful indicator of economic activity.
The more cranes there are, the more construction work is going on.
In 2013 a study by the Health and Safety Executive (which oversees the erection of tower cranes) revealed that 60% of them went up in London, despite the city only having 1 in 8 of the population.
The figures showed that the capital was the economic powerhouse of the UK. And that construction mattered.
Today's construction figures are far from gloomy.
They suggest that over the next year we could be seeing far more cranes as business confidence returns after the concerns of the referendum result.
IHS Markit, which publishes the data, said there was evidence of "a renewed rise in staffing levels across the construction sector and a rebound in business expectations for the next 12 months".