EC 3749 then IB 5412 at Barcelona
Milan → Barcelona → London Gatwick
Timetable, Barcelona time
21:30EC 3749 from Milan at the gate
14:30IB 5412 to London Gatwick leaves the gatealso LL 5412, VY 7616, BA 8070
17 h apart on the timetable, overnight
IB 5412 leaves 17 h after EC 3749 arrives on the timetable: more than half a day, so not a connection we count.