Petrofac leads the oil services sector higher after an upgrade to 'add' from 'neutral' from the broker Evolution Securities in expectation of strong growth from the oil services group's exploration and construction business.Mobile phone stocks are lower after Britain's four mobile phone groups were told to slash charges for calls between different networks and between land lines and mobiles over the next four years by telecoms regulator Ofcom.Vodafone, Orange, O2 and 3UK currently charge either 4.6p or 4.3p a minute for calls to another network - the termination charge. This will fall to 0.5p by 2015 under today's proposals.Shares in Vodafone, the only one of the four with a stock market listing, are lower.Top performing sectors so far todayOil Equipment, Services & Distribution 18,270.51 +3.61%Mining 25,014.35 +2.97%Industrial Metals & Mining 6,989.14 +2.41%Automobiles & Parts 3,299.01 +2.25%Industrial Engineering 4,758.05 +1.75%Bottom performing sectors so far todayMobile Telecommunications 3,485.06 -0.81%Health Care Equipment & Services 3,601.51 -0.24%Pharmaceuticals & Biotechnology 8,828.91 -0.23%Alternative Energy 6,018.42 -0.17%