Two derailments last week have left lines blocked in Sussex and Essex. Inspectors from the Rail Accident Investigation Branch have been examining the evidence from both sites, and there has been speculation that the very hot weather may have been a factor. National Rail has also reported problems with overhead wires on the East Coast Main Line.

Greater Thameslink Railway interim CEO John Whitehurst says the root cause of last night’s derailment near Lewes will be the subject of an ‘open investigation’. Twenty people were injured in the crash, two of them seriously, when the three trailing cars of a Southern train became derailed and overturned in a lineside field.