The six unanswered questions over train crash as investigators try to piece together why express smashed into back of stopped train, killing driver and injuring 99 in worst crash in 20 years

A total of 99 people were injured, 32 seriously, after a Luton Airport Express service ploughed into the back of a Nottingham to St Pancras train at around 5.15pm on Friday.

The six unanswered questions over train crash as investigators try to piece together why express smashed into back of stopped train, killing driver and injuring 99 in worst crash in 20 years
A total of 99 people were injured, 32 seriously, after a Luton Airport Express service ploughed into the back of a Nottingham to St Pancras train at around 5.15pm on Friday.