Worried sire workers contacted the Enquirer following the incident last Thursday.

It is understood the hand rail of a platform on a construction train hit a cable hanging from the side of the tunnel.

The cable snagged and caused an electricty panel box to come off the tunnel wall.

Fortunately the cable and panel were redundant and not live.

The worker said: “The cable got caught on the hand rail and ripped the panel box clean off the wall.

“The cable was snaking all over the place and the panel followed while the handrail was ripped off.

“The cable and panel could easily have hit someone and thankfully they weren’t live or the team on the train and those working down the track could have got a major belt.”

A spokesperson for Crossrail said: “Crossrail demands the highest standards of health and safety and a full investigation into this incident is continuing involving the contractor Alstom, TSO, Costain Joint Venture.”