LONDON (APP/Reuters): British construction activity contracted last month for the first time since February 2010, suggesting the sector will make at best a small contribution to fourth-quarter GDP growth. The Markit/Chartered Institute of Purchasing and Supplys construction index fell to 49.1 from 51.8 in November, three times the drop economists had forecast, and the forward-looking elements of the survey pointed to muted future growth in the sector. Readings below 50 indicate contraction. The survey compilers said poor weather had contributed to the decline. Only commercial construction activity managed to expand, and even here the rate of growth was the slowest in almost a year. Housebuilding saw its sharpest contraction since April 2009 and civil engineering activity also declined. Sterling weakened slightly after the data as investors bet that the sectors strong contribution to GDP growth in the second and third quarters of 2010 was unlikely to be repeated. Even allowing for the hit to activity coming from Decembers severe weather, it is very clear that the economy cannot rely on a major contribution from construction going forward, said Howard Archer at IHS Global Insight.