Irrespective of insurance, you would not be stranded if both airlines were part of the same alliance, yet alone same airline.

The truth is that airlines simply want you put of their way. If there is space on the next flight, you will be on it. That is my experience of 30 years of missing flights.

Now, if youre saying 'can I get insurance to buy me a £5,000 J ticket on Thai to BKK because I missed the BA flight and, whilst they will happily put me on the BA flight tomorrow for free, I want to go tonight?' you can see why that is a big ask.