British Gas owner Centrica confirmed on Tuesday the appoitment of BP executive Iain Conn as its new Chief Executive.Conn will join Centrica at the start of January next year, replacing Sam Laidlaw who will retire from the group at the end of this year.He joins from BP, where he has been Chief Executive of the oil giant's refining and marketing division for the past seven years.Centrica Chairman Rick Haythornthwaite said: "Iain will bring an impressive combination of experience to our business."The appointment of Conn had been widely expected following speculation about the potential retirement of Laidlaw, who headed up the company as it faced criticism for hiking household energy bills while increasing profits.Shares in Centrica rose 0.4p to 315.6p at 16:22 in London, while BP fell 11.6p or 2.3% to 485.2p.PW