Counting tower cranes has long been used as a rule of thumb by experts for assessing construction activity and the number of cranes on the UK's skyline has dropped to its lowest point in over two years. That is according to infrastructure experts at international law firm Pinsent Masons, who have described the situation as: "...symbolic of the sharp falls in new commercial construction, deep cuts in capital spending being made by the public sector, and the current lack of positive UK infrastructure policy."

Data obtained by the firm is the latest evidence of a slowdown in construction activity around the UK, following the completion of various projects related to the Olympics, and is likely to cause further concern around the future of infrastructure spending ahead of next month's Autumn Statement.

Graham Robinson, global business consultant in the infrastructure sector at Pinsent Masons, said: "People often look at the number of cranes as a barometer of the health of UK construction. If that is correct, then we should be concerned. The lack of cranes on UK skylines is symbolic of the sharp falls in new commercial and public-sector construction seen in the last year and the lack of positive UK infrastructure policy. It is also a sign that construction projects are getting smaller, forcing larger construction companies to compete for smaller projects."

By analysing the number of Tower Crane Notifications received by the HSE over the past two years, Pinsent Masons says that it is able to provide a different perspective on construction across the UK.

"Tower cranes are generally only required for major projects, so their absence from the skylines of cities around the UK tells its own story. This is forcing larger construction companies to compete for smaller projects," says Robinson. "The stimulus of the Olympic Games is gone and we have to get clearer commitments from government on a whole raft of policy concerned with building the infrastructure that Britain needs."

The data shows that only 413 tower cranes were erected around the UK in the first six months of 2012 – almost half the figure for the same period in 2011. In London, only 200 cranes appeared on the skyline in the past six months compared to 366 for the same period in 2011, a fall of 45%, while the dearth of major construction projects in UK cities outside London is worse, with an overall fall of over 50%.

Graham Robinson said: "The massive fall in the numbers of tower cranes across the sky lines of the UK's major cities shows just how far workloads have fallen in the construction sector across the UK, driven by the sharp falls in commercial construction and the deep cuts we are seeing in new public-sector construction.

"While the UK economy grew by 1% in the third quarter, the beleaguered construction sector has continued to suffer from a falling workload, with output shrinking by a further 2.6% quarter-on-quarter. This brings output in the sector, which is one of the UK's largest employment industries, down by 11.3% year-on-year with unemployment and insolvencies within the sector increasing as firms struggle with a massive drop in workload.

"With further declines in workload still expected, employment in construction is likely to shrink further with the prospect of further insolvencies across the sector. A bleak winter is predicted for the construction sector."

Picture of tower cranes in Manchester by Chris Stokes