UK construction growth slowed to its weakest pace in six months in September, with the confidence of firms in the sector dampened by political uncertainty and investor concerns over Brexit, a survey shows.

The Chartered Institute of Procurement & Supply’s purchasing managers’ index for the UK construction sector, which measures activity, fell from 52.9 in August to 52.1 last month on a seasonally adjusted basis. While above the level of 50 deemed to separate expansion from contraction, the September reading signals only modest growth.

The civil engineering sub-sector experienced a slightly faster pace of decline in September than in August. Housebuilding and commercial property construction recorded “solid” rates of increase in activity, although CIPS noted that this growth was weaker than in August.

The construction sector last month recorded its fastest growth in new orders since December 2016. Staffing grew at the fastest pace since December 2015.

Tim Moore, associate director at IHS Markit and author of the construction survey, said: “Latest data showed overall confidence about the year-ahead business outlook was among the lowest seen since the start of 2013. Construction companies continued to note that political uncertainty acted [as] a key drag on decision-making, with Brexit worries encouraging a wait-and-see approach to spending among clients.”