Part of the main A47 will be closed over the weekend, as engineers work on a �50m overhead power line upgrade.

The stretch at Pentney, between King's Lynn and Swaffham, West Norfolk, will be closed overnight between Saturday night and Sunday morning.

National Grid is carrying out work on an eight-month project to rewire the 52-mile high-voltage line, running between Norwich and the Walpole substation, near Wisbech.

Engineers are renewing the conductors (wires) and fittings and carrying 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.'

The 400,000 volt power line was built in the early 1960s and now needs refurbishing to cope with greatly increased demand for electricity.

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