The UK railway network was the victim of at least four major cyber attacks in the last 12 months, according to a private security company that works with the network.

The attacks were discovered by Darktrace, a British cybersecurity startup that is responsible for defending most of the UK's railway network.

Dave Palmer, the chief technology officer of Darktrace, said: "In an era of imperfect defences and increasingly complex networks, determined threats can always get in. Today, all businesses can be affected, regardless of size or sector."