LONDON (Dow Jones)--BP PLC (BP) will shut its Unity Riser platform in the North Sea for six days of planned maintenance starting from Aug. 1, a spokesman said Thursday. This is slightly longer than the previously reported three to four days. The Unity Riser platform is a key part of Forties Pipeline System, operated by BP. It connects many fields, including Britannia, Scott, Nelson, Elgin/Franklin and ETAP, to the main oil line to Scotland. However, the largest 200,000-barrel-a-day Buzzard field isn't linked to the platform, according to a map posted on BP's website. -By Sherry Su, Dow Jones Newswires; +44(0)20-7842-9329; sherry.su@dowjones.com (END) Dow Jones Newswires July 29, 2010 10:25 ET (14:25 GMT)