UK Power Networks has defended its plans to cut off electricity at 360 properties in two Norfolk villages for up to nine hours tomorrow.

Homes and businesses in Melton Constable and Briston are due to be cut of from 8am until 5pm to allow �1 million worth of upgrades to be carried out.

A spokesman for UK Power Networks said: 'We have responsibility for 92,000km of power cables in the East of England alone, enough to go around the world almost eight times.

'On-going improvement work is a year-round job and it is not something that we can choose to do at certain times of the year.

'We will never take people off the supply when the temperature is below freezing and if that is the case here then the work will be postponed.'

Engineers have been working in Briston and Melton Constable since Christmas, laying 1km of new cables and installing a new substation.

A spokesman said: 'We have also been able to replace 2km of overhead lines with underground cables, as local people have asked us to. On Wednesday we will be connecting customers' supplies to the new equipment.

'We will have more than 20 staff working to complete it as quickly as is safely possible. We carry out such work all year round but only resort to turning off the power where we absolutely have to. In this case it will be necessary to interrupt 360 power supplies in parts of Melton Constable and Briston from 8am to 5pm, for our engineers to work on the lines in safety - although power will be restored sooner if possible.

'We do appreciate that it is difficult to be without power, particularly during the winter, so we gave all customers whose power will be affected a month's notice to help them to make alternative arrangements such as hiring a generator. If anyone still has any concerns they should please contact us on 0800 7838838. If you have not received a letter your supply will remain unaffected.

'It is important to stress that this work is essential to help ensure reliable power supplies to our customers in the area, for years to come.'

The East of England Co-op in Melton Constable has drafted in a generator will remain open throughout the day.

Glyn Lee, energy manager for the East of England Co-operative Society, said: 'We recognise that our store in Melton Constable provides a vital service to our local members and customers, and the society felt it was important that we put measures in place to ensure that the store stays open.'