Street lights in Oxford could be replaced if a councillor succeeds in his bid to slash the city's energy consumption.o In 2005-2006 Oxford city and Oxfordshire county councils racked up a combined electricity bill of £5million - and civic leaders should realise that something needs to be done.

The warning came from Paul Sargent, the city councillor for Carfax, who earlier this year suggested street lights should be turned off between midnight and 5am.

Now city council leader John Goddard, who has promised to get the Town Hall in order, said he would write to his counterpart at Oxfordshire County Council, Keith Mitchell, challenging him to do the same.

If Mr Mitchell agrees councils and the highways authority would have to undertake an audit of every street light, traffic light and illuminated sign.

Mr Goddard said: "Much of the lighting stock is ageing, energy-inefficient and in some cases polluting.

"Now is a good time for the city and county council to adopt a new approach.

"I will be writing to the leader of the county council to suggest a joint approach to these issues."

His letter will demand that the council investigate the possibility of switching off some lights between midnight and 5am. He also proposes an audit of all lighting to ensure it is correctly positioned and a possible switch to energy-efficient bulbs.

Environmental health officials have powers under the Environmental Protection Act and Clean Neighbourhoods and Environment Act to tackle light pollution.

But Mr Sargent said: "Light pollution occurs from the use of artificial lighting. In some cases, when light is emitted, it can be seen as prejudicial to health or a nuisance."

Earlier this year, the city council hosted a climate change conference, bringing together experts to discuss how the authority could improve its environmental record.

Mr Goddard wants his Liberal Democrat group to make reducing energy consumption one of the cornerstones of their administration.

However, Thames Valley Police would have to undertake crime-risk assessments before permission is given for any lights to be switched off.