A STRETCH of Hampshire motorway will be plunged into darkness overnight in a move to reduce carbon emissions and light pollution.

Highways chiefs will cut the lights between junctions 7 and 8 of the M27 near Southampton in the first scheme of its kind in the south east.

The lights will go out between midnight and 5am from Thursday.

Motoring organisations have questioned the safety of the move and claim improving traffic flow would do far more for the environment.

The Highways Agency insists the stretch at Hedge End was selected for its excellent safety record and a very low traffic flow – averaging one vehicle every ten seconds in the early hours.

A regional control centre will override the automatic switch-off if needed and motorway junctions and their approaches will remain lit.

Jon Griffiths, the agency’s network operations director in the south east, said: “We expect to achieve up to a 40 per cent saving in carbon emissions and energy use for each section of motorway where we do this, and local communities will benefit from reduced light pollution of the night sky.”

Hedge End Town Council said it had received no recent complaints about light pollution from the motorway.

Edmund King, president of the AA, said: “All the evidence shows that lit roads and lit motorways are safer than unlit roads.

“The early hours is when you may have someone falling asleep who needs the lighting on.”

Mr King said using more energy efficient and less intrusive lighting was a better idea.

The Highways Agency expects to reduce carbon emissions from lighting the M27 stretch from 204 to 90 tonnes, and cut its energy bill from £40,400 to £17,797 – although start-up costs mean it will take more than a year to see savings.

An average car produces about three tonnes of carbon a year.