Power was turned off to more than 1,500 properties in the Victoria Road area of the town last night after thieves tried to steal cabling from a substation. Around 150 are still without electricity today.

Engineers switched off supplies to 1,700 homes and businesses after the attempted theft caused a fault on high-voltage underground cables.

UK Power Networks said engineers have worked through the night, checking to ensure internal wiring systems at properties are safe.

All properties fed by the affected underground cables have to be checked before power can be switched back on. This morning about 160 properties remained without power.

UK Power Networks said: 'We would urge anyone affected who has not called us yet to phone us on a free helpline for the East of England - 0800 783 8838 – so we can arrange to visit their properties to carry out the checks.

'Volunteers from the British Red Cross are helping our own customer relations colleagues in the area. The BRC work on our behalf to help give practical support to customers without power.

'They will have the latest information for customers affected by the power cut on how work is progressing and can provide hot drinks to those who need them.

'They will also be calling on any vulnerable customers we are aware of.'

It said it hoped the power would be back on to all those affected by the end of today.

'Late yesterday afternoon, customers started calling in to report fluctuating levels of volts affecting household appliances,' the company said.

'The attempted theft then caused a fault on the high-voltage underground electricity distribution network so, for safety reasons, supplies were interrupted to about 1,700 customers at 6pm.'

Some people reported smoke coming from electrical applicances, as damage to the substation, in Railway Road, caused a power surge.

Engineers on site established which properties were affected by the fault and managed to restore supplies to about 1,500 customers at 7.27pm, with a further 120 customers having power again at 7.43pm.

'We occasionally find that substations and other electrical equipment are targets for thieves and vandals,' UK Power Networks said.

'We take incidents like this very seriously. Thieves risk serious injury and death by tampering with our equipment.

'The police have been informed about this incident and are investigating the circumstances. 'UK Power Networks will press for the prosecution of anyone caught tampering with its network.'