B6 1620 then BA 1326 at Heathrow
Boston → London → Newcastle
Timetable, London time
06:55B6 1620 from Boston at the gate
06:35BA 1326 to Newcastle leaves the gate
23 h 40 apart on the timetable, overnight
BA 1326 leaves 23 h 40 after B6 1620 arrives on the timetable: more than half a day, so not a connection we count.