Complex sentence: They hadn't said what aspects of EU membership they wanted to renegotiate or when they would do it but nearly 340,000 East Midland jobs depended on continued membership and a European referendum would be a distraction when Britain was trying to improve its economy.
Split into simpler sentences: They hadn't said what aspects of EU membership they wanted to renegotiate or when they would do it but nearly 340,000 East Midland jobs depended on continued membership. An EU referendum would be a distraction when Britain was trying to improve its economy.