Thieves risked being electrocuted to steal copper earthing cables from an electricity substation.

The cables were stolen from St Helier electricity substation, in Reigate Avenue, Sutton, between October 13 and 19.

The UK Power Networks substation, which is surrounded by 8ft high fencing, was secured and it is not known how the thieves gained access.

Police were advised by the company that there would have been risk of electrocution during the theft.

The building contains high voltage generators that supplies electricity to most of Sutton and Carshalton.

The theft was discovered when a technician visited the substation on October 19, for a routine inspection that the cables, which are used to earth the site, when he found they were missing.

The previous inspection was on October 13.

Police are appealing for anyone with information on the theft to contact Sutton Police station on 101, or Crimestoppers anonymously on 0800 555 111.

The copper theft is the latest in a string of metal thefts in Sutton.

Thieves recently stripped Carshalton War Memorial of 14 brass plaques and a huge £6000 bronze bell church was taken from St Oswald's Church in North Cheam.

Churches and schools across the borough have reported lead being pinched from their roofs, while railways have seen copper wiring taken from overhead wires.

A number of manhole covers have also been stolen.

The rise in metal theft has been linked to soaring worldwide metal prices.