Carl Icahn, the US activist investor, has signalled the possible launch of a new campaign against Motorola if performance at the telecommunications equipment maker does not improve. Icahn told the FT that “there is value” in Motorola, and “if that value doesn’t manifest itself I, as an activist, would think very seriously about coming back”. Icahn, 71, failed to gain a board seat at Motorola in May after a bitter proxy war that lasted several months.Since that defeat, he has remained a large Motorola shareholder, owning more than 70m shares, or a stake of about 3%, say people familiar with the matter. After pushing earlier in the year for a massive share buyback, Icahn still believes Motorola’s troubled handset division should be separated from the rest of the group. Motorola has disagreed with that assessment.