TU 744 then BA 903 at Frankfurt
Tunis → Frankfurt am Main → London Heathrow
Timetable, Frankfurt am Main time
17:25TU 744 from Tunis at the gate
15:15BA 903 to London Heathrow leaves the gate
21 h 50 apart on the timetable, overnight
BA 903 leaves 21 h 50 after TU 744 arrives on the timetable: more than half a day, so not a connection we count.