Drivers will face road closures and speed restrictions as National Grid carries out a �50m upgrade of overhead power lines running across Norfolk.

Work starts this month on an eight-month project to rewire the 52-mile high-voltage line, running between Norwich and Walpole, near Wisbech.

Engineers will renew the wires and fittings and carry out strengthening work on some of the 224 pylons that carry the wires.

Project manager Simon Chandler said: 'This work will help to ensure that our electricity supply continues to serve us safely, reliably and efficiently for decades to come, securing our energy supply for future generations.

'We apologise for any inconvenience caused, but the road and lane closures are essential for the safety of the public and our workforce. We will make every effort to complete the work as safely, quickly and efficiently as possible.'

The Tilney, Walpole and Necton areas will be affected by the work.

The A47 will be reduced from two lanes to one in each direction with temporary traffic lights from Saturday, April 30, to Sunday, May 1.

This will be in place from the junction with Main Road, Tilney All Saints, to the junction with Church Road, Terrington St John.

The restriction will take place from 8pm on Saturday to 6am on Sunday.

Walpole Bank Road, near Walpole St Peter, will be closed from its junction with Folgate Lane to Wisbech Road for four weeks from Friday, April 29, to Thursday, May 26.

A diversion route will be in place via Wisbech Road, Police Road, Walnut Road, Mill Road, Lynn Road, School Road and Mill Road.

Speed restrictions and temporary traffic lights will be in place on the A47 at Necton overnight from 8pm on Sunday, May 1 to 6am on Monday, May 2.

Temporary speed restrictions – 50mph reducing to 10mph – will be in place from the junction with Moor Lane to south of the junction with Dunham Road.

The 400,000 volt power line was built in the early 1960s and now needs refurbishing.

The work will enable National Grid to increase the capacity of the line and the network in East Anglia to secure future energy supplies.

The project is being carried out by National Grid, leading an electricity alliance with Balfour Beatty.

National Grid is also set to begin work on a new pylon line acrosss the Fens.

It will connect the proposed gas-fired power station in King's Lynn to the existing National Grid network by 2014.

After consulting the public last year, the energy company announced that a route stretching between the Great Ouse Relief Channel and West Winch was its the preferred option.

This option includes the River Nar and the railway line and will see the power line leaving the power station to the south-east to connect to the grid.

The line will be around 1.75 miles in length and National Grid has said the pylons along the route could be 50 metres tall.