TWO police officers and an engineer are being treated for serious burns following an explosion at a vandalised electricity substation.

Police believe that a thief looking for copper piping may also have been injured after breaking into the substation in North Road, Blackburn.

Around 1,500 United Utilities customers in the Shadsworth area were without electricity for three hours due to the resulting power cut.

Pupils at Our Lady and St John's Catholic Arts College, opposite the substation on North Road, were told not to come into school for the day.

United Utilities engineer Keith Shephard visited the site shortly after 3.40am today when an electrical fault was reported.

He discovered that the brick building's door had been forced open and that equipment had been tampered with.

PC Garry Flanagan, 46, and PC Oliver Timperley, 29, were called to the scene at 4.20am but all three were then caught by an electrical flashover.' All three sustained burns to their hands and faces; the engineer also received burns to his arms.

One of the policemen was able to radio for an ambulance. Both officers were taken to Wythenshawe Hospital, where they are still being treated and the engineer was taken to Royal Blackburn Hospital before being released this evening.

Det Chief Insp Paul Withers said: "Their injuries are of a serious nature. This would not have happened if the substation had not been broken into. This person's criminal actions have put lives at risk.

"The price of copper piping has escalated recently, leading to a rise in theft. Substations are very dangerous premises and are regularly broken in to - even though there are clear warning signs. Any unauthorised person entering is putting their life in danger."

A spokesperson for United Utilities said: "Vandalism of substations is a growing problem, both as a result of anti-social behaviour and attempted theft of equipment. Not only does this often lead to the inconvenience of power cuts, it is incredibly dangerous."

A Ennerdale Avenue resident, who asked not to be named, said that he had seen a flash of light through his curtains. He added: "All the lights were out so I had to get my torch and I was bumping into the furniture, but if I hadn't been woken up I doubt I would have noticed a power cut in the middle of the night."

Madeleine Hargreaves, 75, of North Road said: "I thought the clock wasn't working but the power had knocked it off. My husband had to readjust the heating settings because they had been affected."

Les Williams, 69, of Ennerdale Avenue, said: "I didn't know anything about it until I came home in the morning and saw that the clock said 12.27."

College head teacher Colette Gillen said: "My immediate concern was the substation's proximity to the school and I took the decision to close for the day on health and safety grounds."

The school utilised its Keep Kids Safe text message system, sending out messages to parents' mobile phones. Staff praised the success of the system and only a handful of pupils turned up at the gates unaware of what had happened.

Anyone with information about the incident is asked to contact police on 0845 1 25 35 45 or Crimestoppers anonymously on 0800 555 111 .

* One person is in custody in relation to the incident.