LONDON, March 2 (Reuters) - Growth in Britain’s struggling construction industry picked up slightly in February, led by the commercial sector, but uncertainty linked to Brexit continued to weigh on order books, a survey showed on Friday.

FILE PHOTO: Construction cranes are seen on a building site in central London, Britain, July 31, 2017. REUTERS/Hannah McKay/File Photo

The IHS Markit/CIPS UK Construction PMI rose to 51.4 from 50.2 in January, at the top end of forecasts in a Reuters poll of economists that had pointed to a reading of 50.5.

Construction output suffered its biggest drop in more than five years during the final three months of 2017, according to official figures last month, marking the third consecutive quarter of decline.

Year-on-year growth for the economy as a whole in 2017 was the weakest among the G7 group of rich nations during that quarter, partly due to weaker consumer demand caused by higher inflation after June 2016’s Brexit vote.

February’s PMI showed that a sudden drop in housebuilding during January turned out to be a blip, while growth in commercial construction touched a nine-month high.

But the civil engineering sector suffered its worst performance in five months and overall business confidence remained weak. Order books contracted for a second month in a row, boding poorly for future activity.

“The construction sector endured another difficult month during February, with fragile business confidence, entrenched political uncertainty and softer housing market conditions all factors keeping growth in the slow lane,” said Tim Moore, an associate director at IHS Markit, which compiles the PMI.

Some respondents in the survey said Brexit-related uncertainty continued to weigh on decision-making.

Construction makes up only about 6 percent of British economic output but is watched closely as a guide to investment and sentiment in the wider economy.

The closely watched PMI covering the much larger services sector is due on Monday.