An Epsom man has been arrested in connection with an alleged attempt to steal cables from an electrical sub station which left a teenager in a critical condition with horrific burns.

The 17-year-old boy, also from Epsom, sustained the injuries last Friday, June 7. 

A fire officer was flagged down on the A259 at Littlehampton in Sussex at 5.30pm by a motorist who was with the boy, who had burns to his torso, back and arms.

He was taken to the special burns unit at Chelmsford Hospital, in Essex.

A Sussex Police spokeswoman said he has "had surgery and is doing well but remains in a critical condition".

They are investigating the cause of the boy’s injuries, which they believe he sustained in relation to the theft of copper from a substation - part of an electrical generation, transmission and distribution system - at Bilsham Road, in Yapton, near Bognor Regis.

Police said that a 21-year-old man has been arrested on suspicion of theft of metal and has been bailed by police.

Detective Sergeant Sally Arbuckle said: "This young boy has suffered horrific injuries, in what we believe is an attempt to steal cables from electrical substation.

"Substations are extremely dangerous places and should never be entered."

Tim Field, spokesman for the Energy Networks Association (ENA), the industry body for electricity transmission companies, said stealing from substations is incredibly dangerous but teenagers are sometimes willing to risk their lives.

He said: "The electrical shock that you can get can be anywhere from 11,000 volts to 400,000 volts. 

"At the least, it would be incredibly painful and leave you with severe burns. 

"At the worst, the shock would leave nothing more than charred marks on the floor."

He said the wires at the hundreds of thousands of substations across the country are "securely locked away in buildings with ‘danger of death’ signs very clearly visible and barbed-wire fences around them".

Mr Field added: "There is no way that anybody could break into one of these sites trying to steal the cables and not know how dangerous it is. 

"Everything which can be done, within reason, is done."

The price of copper today, according to the London Metal Exchange, is £4492.49 per tonne.

Mr Field said there have been almost 1500 copper thefts against the energy networks so far this year, with the number of attacks against the energy networks in 2012 totalling 4744, and, in 2011, 7629.

He said a report by Deloitte last year calculated that the cost of attacks against the energy networks is £60million a year, with electricity network operators also spending more than £12million a year on security measures to prevent copper theft.

ENA has campaigned for changes to the law, which have now been enacted, to introduce robust licensing requirements for scrap metal dealers, to try and close down the market in stolen metals, which has exploded in recent years due to the rocketing price of metals such as copper.

Anyone with information about this incident should call Sussex Police on 101 quoting the serial number 1192 of 7/6.