BA 853 then VS 358 at Heathrow
Prague → London → Mumbai
Timetable, London time
13:05BA 853 from Prague at the gate
12:25VS 358 to Mumbai leaves the gate
23 h 20 apart on the timetable, overnight
VS 358 leaves 23 h 20 after BA 853 arrives on the timetable: more than half a day, so not a connection we count.