THE rape of a Belgian tourist in a dark alley in Potts Point last month is a warning that environmentally sensitive street lighting will take a terrible human toll.

The 25-year-old was walking down a dimly lit Victoria Street from her serviced apartment to buy food at 8.30pm when a man forced her into the alley between two terrace houses.

It was so dark that the traumatised woman could not give police a description of her assailant, or even tell them the color of his clothes.

The alley where she was attacked is at the northern end of Victoria Street in a residential enclave just a block from the bright lights and fleshpots of Darlinghurst Road.

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And yet the lighting was like something out of the backblocks of St Ives: completely inadequate as a deterrent to crime.

There was a solitary lamp post near where the alley runs into the dead-end Tusculum Lane, positioned 6m south and covered by a tree canopy three storeys high. Nor is there any street light on that side of the road for 50m in the direction the victim was walking.

It was clearly an ideal spot for a predator.

To the council's credit, it has installed three new lights since the assault and is planning to install extra lights at nearby Butler Stairs.

The new lights are the low-energy LED (light-emitting diode) lights which the council is rolling out across Sydney to replace traditional street bulbs.

But the big worry is that LED lights will make Sydney's dim lighting fade even more, thanks to Lord Mayor Clover Moore's jihad against "carbon pollution".

Sure, LED technology is terrific in an enclosed space for focused light but there are drawbacks when it comes to providing uniform illumination for pedestrians to walk safely.

LED lights are white and easier to look at, without the halo effect of traditional street lights. They have the advantage of being more focused so that light doesn't "spill" into houses.

But the light doesn't spread as far, so the area of illumination is smaller. Lighting is further reduced by tree canopies, which abound in areas like Potts Point.

What's more, LED lights don't suddenly blow but degrade over time which means residents may not notice as illumination fades.

And while LEDs measure up to the old lights in "lumen output", the human eye doesn't perceive the same broad coverage.

But street lights are council's biggest single contribution to greenhouse gas emissions and our Lord Mayor is an ardent greenie.

She boasts that Sydney is the first city in Australia to roll out the new lights, after a trial in Alexandria Park, Kings Cross, Martin Place and Circular Quay. The venture will reduce the city's greenhouse gas emissions by 2185 tonnes a year.

The council claims 90 per cent of residents surveyed during their trial found the new lights "appealing".

But when towns in the US and UK have trialled LED lighting residents complained about reduced illumination.

Almost every resident in the two streets in Salford, England, where LED lights were fitted in 2011 signed a petition asking, unsuccessfully, for the old lights to be reinstated.

In Sydney, AUSGRID maintains the traditional street lamps on Victoria Street under contract for the council. A spokesman said yesterday it was in discussions about upgrading lighting there but that council decides how many street lights to install and Standards Australia "dictates how bright lights should be".

You can expect those lights to be dimmer in future since the Australian standard AS/NZS 1158 has been under review to reduce greenhouse gas emissions.

More secret enviro-meddling will come from a body called the "National Strategy on Energy Efficiency" which has been working since 2011 on a plan to "significantly improve street lighting energy efficiency by 2020".

We can assume "improve" is meant in the Orwellian sense, as cities around the world dim their lights.

Electric light has been the wellspring of human progress over the last century, protecting us from the creatures of the night. Now the luddites of the green movement want to send us back to the Dark Ages.

* An earlier version of this column claimed the council had not yet installed lights in the Victoria Street alley. This is not the case. Three new lights have been installed since the attack and the installation of further lights in the area is planned. The Daily Telegraph regrets the error and apologises to the council.