Serco Group said Rupert Soames will join the company as Chief Executive a month earlier than previously planned.Soames will take over on May 1st instead of June 1st and will be appointed to the board at the annual general meeting on May 8th.The grandson of former Prime Minister Winston Churchill replaces Chris Hyman, who was forced to resign last November after the security firm was temporarily banned from winning new work from the UK government for overcharging on the electronic monitoring of criminals. Shares rose 0.19% to 425.40p at 10:16 on Wednesday.RD