David Higgins, chief executive of Network Rail, said: “Last year I apologised in person to the families of Olivia and Charlotte. Today, Network Rail repeats that apology. In this tragic case, Network Rail accepts that it was responsible for failings, and therefore we have pleaded guilty.

“Nothing we can say or do will lessen the pain felt by Olivia and Charlotte’s families but I have promised them that we are committed to making our railway as safe as possible. In recent years we have reassessed all of our 6,500 level crossings and closed over 500. I accept that there is still a long way to go but we are making progress.”