Shares in Immedia jumped 42% after securing BT as the first customer of its mobile audio streaming platform.BT's local network business Openreach will use Immedia's radio channel, where companies will be able to engage directly with their employees and customers through audio content streamed to their mobile phones.The group did not reveal any financial information regarding the one-year long contract with BT.Chief executive Bruno Brookes said: "We are very pleased to be working with the team at Openreach, who truly understand the importance of engaging employees and the value this creates."With its boundless reach, I believe the platform we have created has enormous potential to deliver simple solutions to many global businesses."Shares closed 41.88% higher to 22.7p on Friday.