The FTSE 100 Index was lower in afternoon trading on 4 July after weak construction data weighed on housebuilders.
The Markit/CIPS UK Construction Purchasing Index (PMI) tumbled from 51.2 in May to 46 last month, dropping below the neutral 50 threshold for the first time since 2013. This is the weakest overall performance in the construction industry for seven years.
The news sent blue chip shares down 23.8 points to 6554, as home builders dropped into the red. The FTSE 250 Index was 283.1 points lower at 16,183.1.
Persimmon slipped more than 5%, or 79p to 1456p, Taylor Wimpey fell 6.7p to 131.6p, and Barratt Developments was 19.2p lower at 395.8p.
Construction suppliers also suffered an investor sell-off. Builders' Merchant Travis Perkins fell 41p to 1412p and Plumb Centre owner Wolseley slumped 64p to 3912p.
Spreadex financial analyst Connor Campbell said: "The latest construction PMI seems to portend what the kind of data the UK can expect in the coming months. It's the first concrete, non-market related sign that the Brexit - at least the run-up to the referendum - has done some economic damage to the UK, and has caused the FTSE's early gains to peter out."
Sainsbury's was down 4.3p to 231.8p, after the supermarket chain said it will close its 16 Netto stores after abandoning a joint venture with its Danish retail partner after just two years.
In afternoon trading the top risers in the FTSE 100 Index were Fresnillo (+6.7% to 1878p), Randgold Resources (+4.3% to 9,155p), Glencore (+3.6% to 161.6p) and BHP Billiton (+2.7% to 965.3p).
The top fallers in the FTSE 100 Index were British Land (-7.9% to 560.5p), Land Securities (-6.6% to 970.5p), Taylor Wimpey (-5.5% to 131.6p), Persimmon (-5.5% to 1456p) and Berkeley Group (-5.3% to 2513p).
In afternoon trading the top risers in the FTSE 250 Index were Hochschild Mining (+3.4% to 203.2%), Daejan Holdings, (+2.88 to 4988p), Bodycote (+2.2% at 540.5p), Acacia Mining (+2.1% at 473.5p) and Polymetal International (+2% to 1,080p).
The top fallers in the FTSE 250 Index were Clarkson (-14.7% to 1880p), Moneysupermarket.com Group (-10.65% to 246p), Rightmove (-7.5% to 3457p), Shawbrook Group (-7% to 161.6p) and Zoopla (-5.9% at 249p).