It is not known if the 44-year-old, from Liskeard in Cornwall will ever recover from the debilitating condition which has already seen him lose his job as a signalman for Network Rail.

He was exposed to unknown fumes escaping from a faulty electrical box whilst working at Lostwithiel signal box.

The fumes caused him to become unwell immediately. Initially he suffered from a burning sensation in his chest and nose, dizziness and pain in his limbs. Over the following weeks and months his symptoms worsened.

Some days he is in so much pain he cannot get out of bed. He suffers from poor memory and at times finds it difficult to breathe.

He has been diagnosed with chemically induced CFS with a 60% disability and can no longer work.

Following the accident he attempted to return to his job but in the end was signed off on long term sick and eventually had his contract terminated as he couldn't do his job.

The signalman with 18 years experience says he hopes one day that he will be able to get the chronic condition under control sufficiently to allow him to return to work.

After the accident he was advised by his trade union, the RMT, to pursue a claim for compensation. He instructed the RMT’s lawyers, Thompsons Solicitors.

Thompsons argued that Network Rail should have made sure the electrical box was well maintained and placed in a safer location.

Network Rail admitted liability and settled the claim out of court.

The RMT member said: “The last few years have been a living nightmare. The onset of CFS was immediate from the point I was exposed to the fumes. The symptoms can vary from day to day. On a bad day I can’t get out of bed but on a good day I’m able to walk around gently.

“I am learning to pace myself but I find my condition extremely frustrating. It was a relief when I was finally diagnosed, you begin to think it is all in your head but at the same time you know it isn't. I just wish that my employers had ensured I was never exposed to those fumes in the first place.”

Bob Crow, general secretary at the RMT said: “Signalmen play an important role in ensuring the railways run smoothly and are responsible for ensuring that millions of passengers reach their destinations on time. It isn't a lot to ask that Network Rail provide its employees with a safe environment to allow them to continue to do their job as best they can.”

Kevin Digby from Thompsons Solicitors added: “Our client’s life has been turned upside down by this accident which could have been avoided had this antiquated electrical box been updated and maintained properly. We hope this compensation will help him as he learns to adapt and cope with this debilitating condition.”